Windows XP

Windows XP is an operating system produced by Microsoft for use on personal computers, including home and business desktops, laptops and media centers. First released to computer manufacturers on August 24, 2001, it is the second most popular version of Windows, based on installed user base as of 2011. The name "XP" is short for "eXPerience", highlighting the enhanced user experience.

Windows XP, the successor to Windows 2000 and Windows ME, was the first consumer-oriented operating system produced by Microsoft to be built on the Windows NT kernel. Windows XP was released worldwide for retail sale on October 25, 2001, and over 400 million copies were in use in January 2006. It was succeeded by Windows Vista in January 2007. Direct OEM and retail sales of Windows XP ceased on June 30, 2008. Microsoft continued to sell Windows XP through their System Builders (smaller OEMs who sell assembled computers) program until January 31, 2009. On April 10, 2012, Microsoft reaffirmed that extended support for Windows XP and Office 2003 would end on April 8, 2014 and suggested that administrators begin preparing to migrate to a newer OS. But on January 17, 2014 Microsoft confirmed that Monthly Microsoft's Malicious Software Removal Tool (MSRT) which aligned with Microsoft's anti-malware engines and signature still available until July 14, 2015. XP users can download the software from its website manually.

The NT-based versions of Windows, which are programmed in C, C++, and assembly, are known for their improved stability and efficiency over the 9x versions of Microsoft Windows. Windows XP presented a significantly redesigned graphical user interface, a change Microsoft promoted as more user-friendly than previous versions of Windows. In an attempt to further ameliorate the "DLL hell" that plagued the past versions of Windows, improved side-by-side assembly technology in Windows XP allows side-by-side installation, registration and servicing of multiple versions of globally shared software components in full isolation. It is also the first version of Windows to use product activation in an effort to reduce software piracy.

During Windows XP's development, the project was codenamed "Whistler", after Whistler, British Columbia, as many Microsoft employees skied at the Whistler-Blackcomb ski resort.

According to web analytics data generated by Net Applications, Windows XP was the most widely used operating system until August 2012, when Windows 7 overtook it. , Windows XP market share is at 28.98%, having decreased almost every month since at least November 2007, the first month for which statistics are publicly available from Net Applications.

As "Neptune"
In the late 1990s, initial development of what would become Windows XP was focused on two individual products; Odyssey, which was reportedly intended to succeed Windows 2000, and Neptune, which was intended to succeed the MS-DOS-based Windows 98 with a Windows NT-based product designed for consumers. Based off 2000's NT 5.0 kernel, Neptune primarily focused on offering a simplified, task-based interface based around a concept known internally as "activity centers". A number of "activity centers" were planned, serving as hubs for communications (i.e. email), playing music, managing or viewing photos, searching the internet, and viewing recently used content. A single build of Neptune, 5111 (which was otherwise based on, and still carried Windows 2000 branding in places), revealed early work on the activity center concept, with an updated user account interface and graphical login screen, common functions (such as recently used programs) being accessible from a customizable "Starting Places" page (which could be used as either a separate window, or a full-screen desktop replacement).

However, the project, at its current state, proved to be too ambitious. The company shelved Bill Gates' 1998 promise that Windows 98 would be the final DOS-based version of Windows by releasing Windows 98 Second Edition, and at the WinHEC conference on April 7, 1999, Steve Ballmer announced Windows Millennium (Windows ME). Microsoft also planned to push back Neptune in favor of an interim, but consumer-oriented NT-based OS codenamed "Asteroid". Concepts introduced by Neptune would eventually influence future Windows versions; in Windows ME, the concept was used for System Restore and Help and Support (which both combined Win32 code with an interface rendered using Internet Explorer's layout engine), the hub concept would be expanded on Windows Phone, and Windows 8 would similarly use a simplified user interface running atop the existing Windows shell.

As "Whistler"
In January 2000, shortly after the release of Windows 2000, technology writer Paul Thurrott reported that Microsoft had shelved both Neptune and Odyssey in favor of a new product codenamed Whistler, which planned to unify both the consumer and business-oriented Windows lines under a single, Windows NT platform, further stating that "Neptune became a black hole when all the features that were cut from [Windows ME] were simply re-tagged as Neptune features. And since Neptune and Odyssey would be based on the same code-base anyway, it made sense to combine them into a single project". At WinHEC in April 2000, Microsoft officially announced and presented an early build of Whistler, focusing on a new modularized architecture, built-in CD burning, fast user switching, and updated versions of the digital media features introduced by ME. Windows general manager Carl Stork stated that Whistler would be released in both consumer- and business-oriented versions built atop the same architecture, and that there were plans to update the Windows interface to make it "warmer and more friendly".

In June 2000, Microsoft began the technical beta testing process; Whistler was expected to be made available in "Personal", "Professional", "Server", "Advanced Server", and "Datacenter" editions. At PDC on July 13, 2000, Microsoft announced that Whistler would be released during the second half of 2001, and also released the first preview build, 2250. The build notably introduced an early version of a new visual styles system along with an interim theme known as "Professional" (later renamed "Watercolor"), and contained a hidden "Start page" (a full-screen page similar to Neptune's "Starting Places"), and a hidden, early version of a two-column Start menu design. Build 2257 featured further refinements to the Watercolor theme, along with the official introduction of the two-column Start menu, and the addition of an early version of Windows Firewall.

Beta releases
Microsoft released Whistler Beta 1, build 2296, on October 31, 2000. Build 2410 in January 2001 introduced Internet Explorer 6.0 (previously branded as 5.6) and the Windows Product Activation system. Bill Gates dedicated a portion of his keynote at Consumer Electronics Show to discuss Whistler, explaining that the OS would bring "[the] dependability of our highest end corporate desktop, and total dependability, to the home", but also "move it in the direction of making it very consumer-oriented. Making it very friendly for the home user to use." Builds 2416 and 2419 added the File and Transfer Settings Wizard and began to introduce elements of the operating system's final appearance (such as its near-final Windows Setup design, and the addition of new default wallpapers, such as Bliss).

On February 5, 2001, Microsoft officially announced that Whistler would be known as Windows XP, short for "experience". As a compliment, the next version of Microsoft Office was also announced as Office XP. Microsoft stated that the name "[symbolizes] the rich and extended user experiences Windows and Office can offer by embracing Web services that span a broad range of devices." In a press event at EMP Museum in Seattle on February 13, 2001. Microsoft publicly unveiled the new "Luna" user interface of Windows XP. Windows XP Beta 2, build 2462a (which among other improvements, introduced the Luna style), was launched at WinHEC on March 25, 2001.

In April 2001, Microsoft controversially announced that XP would not integrate support for Bluetooth or USB 2.0 on launch, requiring the use of third-party drivers. Critics felt that in the case of the latter, Microsoft's decision had delivered a potential blow to the adoption of USB 2.0, as XP was to provide support for the competing, Apple-developed FireWire standard instead. A representative stated that the company had "[recognized] the importance of USB 2.0 as a newly emerging standard and is evaluating the best mechanism for making it available to Windows XP users after the initial release." The builds prior to and following Release Candidate 1 (build 2505), released on July 5, 2001, and Release Candidate 2 (build 2526, released on July 27, 2001), focused on fixing bugs, acknowledging user feedback, and other final tweaks before the RTM build.

RTM and release
On August 24, 2001, Windows XP, build 2600, was released to manufacturing. During a ceremonial media event at Microsoft Redmond Campus, copies of the RTM build were given to representatives of several major PC manufacturers in briefcases, who then flew off on XP-branded helicopters. While PC manufacturers would be able to release devices running XP beginning on September 24, 2001, XP was expected to reach general, retail availability on October 25, 2001. On the same day, Microsoft also announced the final retail pricing of XP's two main editions, "Home" and "Professional".

In June 2001, Microsoft indicated that it was planning to, in conjunction with Intel and other PC makers, spend at least US$1 billion on marketing and promoting Windows XP.

User interface
Windows XP featured a new task-based GUI (Graphical user interface). The Start menu and taskbar were updated and many visual effects were added, including:
 * A translucent blue selection rectangle in Windows Explorer
 * Drop shadows for icon labels on the desktop
 * Task-based sidebars in Explorer windows ("common tasks")
 * The ability to group the taskbar buttons of the windows of one application into one button, with a popup menu listing the window titles
 * The ability to lock the taskbar to prevent accidental changes (Windows 2000 with Internet Explorer 6 installed had the ability to lock Windows Explorer and Internet Explorer toolbars, but not the taskbar)
 * The highlighting of recently added programs on the Start menu
 * Shadows under menus (Windows 2000 had shadows under mouse pointers, but not menus)

Windows XP analyzes the performance impact of visual effects and uses this to determine whether to enable them, so as to prevent the new functionality from consuming excessive additional processing overhead. Users can further customize these settings. Some effects, such as alpha compositing (transparency and fading), are handled entirely by many newer video cards. However, if the video card is not capable of hardware alpha blending, performance can be substantially degraded, and Microsoft recommends the feature should be turned off manually. Windows XP added the ability for Windows to use "Visual Styles" to change the appearance of the user interface. However, visual styles must be cryptographically signed by Microsoft to run. Luna is the name of the new visual style that is provided with Windows XP, and is enabled by default for machines with more than 64 MiB of RAM. Luna refers only to one particular visual style, not to all of the new user interface features of Windows XP as a whole. Some users "patch" the  file that restricts the ability to use visual styles, created by the general public or the user, on Windows XP.

In addition to the included Windows XP themes, there is one previously unreleased theme with a dark blue taskbar and window bars similar to Windows Vista titled "Royale Noir" available as unofficial download. Microsoft officially released a modified version of this theme as the "Zune" theme, to celebrate the launch of its Zune portable media player in November 2006. The differences are only visual with a new glassy look along with a black taskbar instead of dark blue and an orange start button instead of green. Additionally, the Media Center "Royale" theme, which was included in the Media Center editions, is also available to download for use on all Windows XP editions.

The default wallpaper, Bliss, is a photo of a landscape in the Napa Valley outside Napa, California, with rolling green hills and a blue sky with stratocumulus and cirrus clouds.

The "classic" interface from Windows 9x and 2000 can be used instead if preferred. Several third party utilities exist that provide hundreds of different visual styles.

Other features

 * GDI+ graphics subsystem and improved image management and viewing in the shell
 * DirectX 8.1 upgradeable to DirectX 9.0c
 * A number of new features in Windows Explorer including task panes, tiles and filmstrip views, improved sorting and grouping, searching by document categories, customizable infotips, built-in CD burning, AutoPlay, Simple File Sharing and WebDAV mini-redirector.
 * Improved imaging features such as Windows Picture and Fax Viewer, improved image handling and thumbnail caching in Explorer
 * A number of kernel enhancements and power management improvements
 * Faster start-up, (due to improved Prefetch functions) logon, logoff, hibernation and application launch sequences.
 * The ability to discard a newer device driver in favor of the previous one (known as driver rollback) should a driver upgrade not produce desirable results.
 * Numerous improvements to increase the system reliability such as improved System Restore, Automated System Recovery, Windows Error Reporting and driver reliability.
 * A new, arguably more user-friendly interface, including the framework for developing themes for the desktop environment and richer icons with alpha transparency
 * Hardware support improvements such as USB 2.0, FireWire 800, Windows Image Acquisition, Media Transfer Protocol, DualView for multi-monitors and audio improvements.


 * Fast user switching, which allows users to save the current state and open applications of their desktop and allows another user to log on without losing that information
 * The ClearType font rendering mechanism, which is designed to improve text readability on liquid crystal display (LCD) and similar monitors, especially laptops.
 * Remote Assistance and Remote Desktop features, which allow users to connect to a computer running Windows XP from across a network or the Internet and access their applications, files, printers, and devices or request help.
 * New networking features including Windows Firewall, Internet Connection Sharing integration with UPnP, NAT traversal APIs, Quality of Service features, IPv6 and Teredo tunneling, Background Intelligent Transfer Service, extended fax features, network bridging, peer to peer networking, support for most DSL modems, IEEE 802.11 (Wi-Fi) connections with auto configuration and roaming, TAPI 3.1, Bluetooth and networking over FireWire.
 * New security features such as Software Restriction Policies, Credential Manager, Encrypting File System improvements, improved certificate services, smart card and PKI support. Windows XP SP2 introduced Data Execution Prevention, Windows Security Center and Attachment Manager.
 * Side-by-side assemblies and registration-free COM
 * Improved media features in Windows Media format runtime, Windows Media Player, Windows Movie Maker, TV/video capture and playback technologies, Windows Media Encoder and introduction of Windows Media Center
 * General improvements to international support such as more locales, languages and scripts, MUI support in Terminal Services, improved IMEs and National Language Support, Text Services Framework
 * Handwriting recognition, speech recognition and digital ink support accessible through the Tablet PC Input Panel (TIP) in Windows XP Tablet PC Edition
 * Numerous improvements to system administration tools such as Windows Installer, Windows Script Host, Disk Defragmenter, Windows Task Manager, Group Policy, CHKDSK, NTBackup, Microsoft Management Console, Shadow Copy, Registry Editor, Sysprep and WMI
 * Improved application compatibility and shims compared to Windows 2000
 * Updated accessories and games.
 * Improvements to IntelliMirror features such as Offline Files, Roaming user profiles and Folder redirection.

Users in British schools observed the improved ease of use and advanced capabilities – comparing the former to and, and the latter to Unix.

Removed features
Some of the programs and features that were part of the previous versions of Windows did not make it to Windows XP. CD Player, DVD Player and Imaging for Windows are removed as Windows Picture and Fax Viewer, Windows Media Player and Windows shell take over their duties. NetBEUI and NetDDE are deprecated and are not installed by default. DLC and AppleTalk network protocols are removed. Plug-and-play–incompatible communication devices (like modems and network interface cards) are no longer supported.

Service Pack 2 and Service Pack 3 also remove features from Windows XP but to a less noticeable extent. For instance, Program Manager and support for TCP half-open connections are removed in Service Pack 2. Energy Star logo and the address bar on taskbar are removed in Service Pack 3.

Editions


The two major editions are Windows XP Home Edition, designed for home users, and Windows XP Professional, designed for business and power users. XP Professional contains advanced features that the average home user would not use. However, these features are not necessarily missing from XP Home. They are simply disabled, but are there and can become functional. These releases were made available at retail outlets that sell computer software, and were preinstalled on computers sold by major computer manufacturers. A third edition, called Windows XP Media Center Edition, was introduced in 2002 and was updated every year until 2006 to incorporate new digital media, broadcast television and Media Center Extender capabilities. Unlike the Home and Professional edition, it was never made available for retail purchase, and was typically either sold through OEM channels, or was preinstalled on computers that were typically marketed as "media center PCs".

Two different 64-bit editions were made available. One, designed specifically for Itanium-based workstations, was introduced in 2001 at around the same time as the Home and Professional editions, but was discontinued a few years later when vendors of Itanium hardware stopped selling workstation-class machines due to low sales. The other, called Windows XP Professional x64 Edition, supports the x86-64 extension. x86-64 was implemented first by AMD as "AMD64", found in AMD's Opteron and Athlon 64 chips, and later implemented by Intel as "Intel 64" (formerly known as IA-32e and EM64T), found in some of Intel's Pentium 4 and later chips.

Windows XP Tablet PC Edition was produced for a class of specially designed notebook/laptop computers called tablet PCs. It is compatible with a pen-sensitive screen, supporting handwritten notes and portrait-oriented screens.

Microsoft also released Windows XP Embedded, an edition for specific consumer electronics, set-top boxes, kiosks/ATMs, medical devices, arcade video games, point-of-sale terminals, and Voice over Internet Protocol (VoIP) components. In July 2006, Microsoft released Windows Fundamentals for Legacy PCs, a thin client version of Windows XP Embedded which targets older machines (as early as the original Pentium). It is only available to Software Assurance customers. It is intended for corporate customers who may wish to upgrade to Windows XP so they can take advantage of its security and management capabilities, but cannot afford to purchase new hardware.

Editions for specific markets
Windows XP Starter Edition is a lower-cost edition of Windows XP available in Thailand, Indonesia, Russia, India, Colombia, Brazil, Argentina, Peru, Bolivia, Chile, Mexico, Ecuador, Uruguay, Pakistan and Venezuela. It is similar to Windows XP Home, but is limited to low-end hardware, can only run three programs at a time, and has some other features either removed or disabled by default. Each country's edition is also customized for that country, including desktop backgrounds of popular locations, localized help features for those who may not speak English, and other default settings designed for easier use than typical Windows XP installations. The Malaysian version, for example, contains a desktop background of the Kuala Lumpur skyline.

In March 2004, the European Commission fined Microsoft €497 million (US$603 million) and ordered the company to provide a version of Windows without Windows Media Player. The Commission concluded that Microsoft "broke European Union competition law by leveraging its near monopoly in the market for PC operating systems onto the markets for work group server operating systems and for media players". After unsuccessful appeals in 2004 and 2005, Microsoft reached an agreement with the Commission where it would release a court-compliant version, Windows XP Edition N. This version does not include the company's Windows Media Player but instead encourages users to pick and download their own media player. Microsoft wanted to call this version Reduced Media Edition, but EU regulators objected and suggested the Edition N name, with the N signifying "not with Media Player" for both Home and Professional editions of Windows XP. Because it is sold at the same price as the version with Windows Media Player included, Dell, Hewlett-Packard, Lenovo and Fujitsu Siemens have chosen not to stock the product. However, Dell did offer the operating system for a short time. Consumer interest has been low, with roughly 1,500 units shipped to OEMs, and no reported sales to consumers.

In December 2005, the Korean Fair Trade Commission ordered Microsoft to make available editions of Windows XP and Windows Server 2003 that do not contain Windows Media Player or Windows Messenger. Like the European Commission decision, this decision was based on the grounds that Microsoft had abused its dominant position in the market to push other products onto consumers. Unlike that decision, however, Microsoft was also forced to withdraw the non-compliant versions of Windows from the South Korean market. This decision resulted in Microsoft's releasing "K" and "KN" variants of the Home and Professional editions in August 2006.

That same year, Microsoft also released two additional editions of Windows XP Home Edition directed towards subscription-based and pay-as-you-go pricing models. These editions, released as part of Microsoft's FlexGo initiative, are used in conjunction with a hardware component to enforce time limitations on the usage of Windows. Its target market is emerging economies such as Brazil and Vietnam.

Languages
Windows XP was available in many languages. In addition, MUI packs and Language Interface Packs translating the user interface were also available for certain languages.

ATMs and Vendors
Automated teller machine (ATM) vendors Wincor Nixdorf, NCR Corporation and Diebold Incorporated all adopted Microsoft Windows XP as their migration path from OS/2; the migration began in 2003 in response to IBM's planned 2006 EOL date for OS/2.

Wincor Nixdorf, which has been pushing for standardization for many years, began shipping ATMs with Windows when they first arrived on the scene.

Diebold initially shipped XP Home Edition exclusively, but following extensive pressure from customer banks to support a common operating system, it switched to support XP Professional to match its primary competitors, NCR Corporation and Wincor Nixdorf.

Redbox DVD Vending machines run a modified version of XP designed for the fullscreen User Interface of the Vending Touchscreen and the DVD vending itself.

In January 2014, it was estimated that more than 95% of the 3 million ATMs in the world were still running Windows XP. Plans were being made by several ATM vendors and their customers to migrate from XP to Windows 7 systems over the course of 2014.

Service packs
Microsoft occasionally releases service packs for its Windows operating systems to fix problems and add features. Each service pack is a superset of all previous service packs and patches so that only the latest service pack needs to be installed, and also includes new revisions. However if you still have the earliest version of Windows XP on Retail CD (without any service packs included), you will need to install SP1 or SP2, before SP3 can be installed. Older service packs need not be manually removed before application of the most recent one. Windows Update "normally" takes care of automatically removing unnecessary files.

Windows XP was criticized by some users for security vulnerabilities, tight integration of applications such as Internet Explorer 6 and Windows Media Player, and for aspects of its default user interface. Service Pack 2, Service Pack 3, and Internet Explorer 8 addressed some of these concerns.

The service pack details below only apply to the 32-bit editions. Windows XP Professional x64 Edition was based on Windows Server 2003 with Service Pack 1 and claimed to be "SP1" in system properties from the initial release. It is updated by the same service packs and hotfixes as the x64 edition of Windows Server 2003.

Service Pack 1
Service Pack 1 (SP1) for Windows XP was released on September 9, 2002. It contains post-RTM security fixes and hot-fixes, compatibility updates, optional .NET Framework support, enabling technologies for new devices such as Tablet PCs, and a new Windows Messenger 4.7 version. The most notable new features were USB 2.0 support and a Set Program Access and Defaults utility that aimed at hiding various middleware products. Users can control the default application for activities such as web browsing and instant messaging, as well as hide access to some of Microsoft's bundled programs. This utility was first brought into the older Windows 2000 operating system with its Service Pack 3. This Service Pack supported SATA and hard drives that were larger than 137 GB (48-bit LBA support) by default. The Microsoft Java Virtual Machine, which was not in the RTM version, appeared in this Service Pack. It also removed the Energy Star logo from the ScreenSaver tab of the Display properties, leaving a very noticeable blank space next to the link to enter the Power Management control panel. Support for IPv6 was also introduced in this Service Pack.

On February 3, 2003, Microsoft released Service Pack 1a (SP1a). This release removed Microsoft's Java virtual machine as a result of a lawsuit with Sun Microsystems.

Service Pack 2
Service Pack 2 (SP2) was released on August 25, 2004, with an emphasis on security. Unlike the previous service pack, SP2 added new functionality to Windows XP, such as WPA encryption compatibility and improved Wi-Fi support (with a wizard utility), a pop-up ad blocker for Internet Explorer 6, and partial Bluetooth support. The new welcome screen during the kernel boot removes the subtitles "Professional", "Home Edition" and "Embedded" since Microsoft introduced new Windows XP editions prior to the release of SP2. The green loading bar in Home Edition and the yellow one in Embedded were replaced with the blue bar, seen in Professional and other versions of Windows XP, making the boot-screen of operating systems resemble each other. Colors in other areas, such as Control Panel and the Help and Support tool, remained as before.

Service Pack 2 also added new security enhancements (codenamed "Springboard"), which included a major revision to the included firewall that was renamed to Windows Firewall and became enabled by default, Data Execution Prevention, which can be weakly emulated, gains hardware support in the NX bit that can stop some forms of buffer overflow attacks. Also raw socket support is removed (which supposedly limits the damage done by zombie machines). Additionally, security-related improvements were made to e-mail and web browsing. Windows XP Service Pack 2 includes the Windows Security Center, which provides a general overview of security on the system, including the state of antivirus software, Windows Update, and the new Windows Firewall. Third-party anti-virus and firewall applications can interface with the new Security Center.

Service Pack 2b
In August 2006, Microsoft released updated installation media for Windows XP SP2 and Windows Server 2003 SP1 to contain a patch that requires ActiveX controls to require manual activation in accordance with a patent held by Eolas. Since then, the technology was licensed by Microsoft, and Service Pack 3 and later versions do not include this update.

Service Pack 2c
On August 10, 2007, Microsoft announced a minor update to Service Pack 2, called Service Pack 2c (SP2c). The update fixes the issue of the diminishing number of available product keys for Windows XP. This update was only available to system builders from their distributors in Windows XP Professional and Windows XP Professional N operating systems. SP2c was released in September 2007.

Service Pack 3
Windows XP Service Pack 3 (SP3) was released to manufacturing on April 21, 2008, and to the public via both the Microsoft Download Center and Windows Update on May 6, 2008.

It began being automatically pushed out to Automatic Update users on July 10, 2008. A feature set overview which details new features available separately as stand-alone updates to Windows XP, as well as backported features from Windows Vista, has been posted by Microsoft. A total of 1,174 fixes have been included in SP3. Service Pack 3 can be installed on systems with Internet Explorer versions 6, 7, or 8. Internet Explorer 7 and 8 are not included as part of SP3. Service Pack 3 is not available for the 64 bit version of Windows XP.

New features in Service Pack 3

 * NX APIs for application developers to enable Data Execution Prevention for their code, independent of system-wide compatibility enforcement settings
 * Turns black hole router detection on by default
 * Support for SHA-2 signatures in X.509 certificates
 * Network Access Protection client
 * Group Policy support for IEEE 802.1X authentication for wired network adapters.
 * Credential Security Support Provider
 * Descriptive Security options in Group Policy/Local Security Policy user interface
 * An updated version of the Microsoft Enhanced Cryptographic Provider Module (RSAENH) that is FIPS 140-2 certified (SHA-256, SHA-384 and SHA-512 algorithms)
 * Installing without requiring a product key during setup for retail and OEM versions

Previously released updates
Service Pack 3 also incorporated several previously released key updates for Windows XP, which were not included up to SP2, including:
 * Windows Imaging Component
 * IPSec Simple Policy Update for simplified creation and maintenance of IPSec filters
 * Background Intelligent Transfer Service (BITS) 2.5
 * MSXML 6.0 SP2 and XMLLite
 * Microsoft Management Console 3.0
 * Credential Roaming service (Digital Identity Management Service) update
 * Remote Desktop Protocol 6.1
 * Peer Name Resolution Protocol 2.1
 * Network Diagnostics update
 * WPA2 Update (KB893357)
 * Windows Script 5.7
 * Windows Installer 3.1 v2
 * Wireless LAN API (KB918997)
 * Improvements made to Windows Management Instrumentation in Windows Vista to reduce the possibility of corruption of the WMI repository.

Slipstreamed retail and OEM versions of Windows XP with SP3 can be installed and run with full functionality for 30 days without a product key, after which time the user will be prompted to enter a valid key and activate the installation. Volume license key (VLK) versions still require entering a product key before beginning installation.

Windows XP Service Pack 3 is a cumulative update of all previous service packs for XP. The service pack installer checks HKLM\SYSTEM\CurrentControlSet\Control\Windows\CSDVersion registry key to see if has a value greater than or equal to 0x100, and if it does it will allow the update to proceed. Otherwise it will prompt to install either XP SP1 or SP2. Since SP1 is no longer available for full download, it would need to be downloaded using Windows Update. The other option is to manually change the registry key, in essence fooling the installer into thinking SP1 is already installed.

However, it is possible to slipstream SP3 into the Windows XP setup files at any service pack level, including the original RTM version, without any errors or issues. Microsoft has confirmed that this is supported, but also that slipstreaming SP3 into a volume license copy of XP using Windows Vista or Windows Server 2008 causes the product key to be rejected during installation. Slipstreaming SP3 into Windows XP Media Center Edition 2005 is not supported.

Service Pack 3 contains updates to the operating system components of Windows XP Media Center Edition (MCE) and Windows XP Tablet PC Edition, and security updates for .NET Framework version 1.0, which is included in these editions. However, it does not include update rollups for the Windows Media Center application in Windows XP MCE 2005. SP3 also omits security updates for Windows Media Player 10, although the player is included in Windows XP MCE 2005. The Address Bar DeskBand on the Taskbar is no longer included due to legal restrictions.

System requirements
System requirements for Windows XP Home Edition and Professional are as follows:

System requirements for Windows XP Professional x64 Edition are as follows:
 * Processor: x86-64 processor;
 * Memory: At least 256 MB of RAM;
 * Video adapter and monitor: Super VGA (800 x 600) or higher resolution;
 * Hard drive disk free space: At least 1.5 GB;
 * Optical drive: CD-ROM drive;
 * Input devices: Keyboard; Microsoft Mouse or compatible pointing device;
 * Sound: Sound card; Speakers or headphones;
 * Drivers for sound card, GPU of video card, wired LAN card, etc. must be designed for Windows XP Professional x64 Edition.

System requirements for Windows XP 64-Bit Edition are as follows:
 * Processor: Intel Itanium 733 MHz (Recommended: Intel Itanium 800 MHz or better);
 * Memory: At least 1 GB of RAM;
 * Video adapter and monitor: Super VGA (800 x 600) or higher resolution;
 * Hard drive disk free space: At least 6 GB;
 * Optical drive: CD-ROM drive;
 * Input devices: Keyboard; Microsoft Mouse or compatible pointing device;
 * Sound: Sound card; Speakers or headphones;
 * Drivers for sound card, GPU of video card, wired LAN card, etc. must be designed for Windows XP 64-Bit Edition.

Physical memory limits
Maximum limits on physical memory (RAM) that Windows XP can address vary depending on both the Windows version and between 32-bit and 64-bit versions. The following table specifies the maximum physical memory limits supported:

Processor limits
The maximum total number of logical processors in a PC that Windows XP supports is: 32 for 32-bit; 64 for 64-bit.

The maximum number of physical processors in a PC that Windows XP supports is: 2 for Professional; and 1 for the Home Edition.

Support lifecycle
Support for Windows XP Home edition and Professional edition without a service pack ended on September 30, 2005. Windows XP Service Pack 1 and 1a were retired on October 10, 2006 and Windows XP Service Pack 2 reached end of support on July 13, 2010, almost six years after its general availability.

The company stopped general licensing of Windows XP to OEMs and terminated retail sales of the operating system on June 30, 2008, 17 months after the release of Windows Vista. However, an exception was announced on April 3, 2008, for OEMs installing to ultra low-cost PCs (ULCPCs) until one year after the availability of Windows 7 (that is, until October 22, 2010).

On April 14, 2009, Windows XP and its family of operating systems reached the end of their mainstream support period and entered the extended support phase as it marks the progression of the legacy operating system through the Microsoft Support Lifecycle Policy. During the extended support phase, Microsoft continues to provide security updates every month for Windows XP; however, free technical support, warranty claims, and design changes are no longer being offered. Extended support will end on January 2, 2012; and it was unsupported.

Downgrade rights
Customers licensed for use of Windows 8 Enterprise are generally licensed for Windows 8 Pro, which may be downgraded to Windows XP Professional. End users of licenses of Windows 7 acquired through OEM or volume licensing may downgrade to the equivalent edition of Windows XP. End users of licenses of Windows Vista Business or Ultimate acquired through OEM have rights to downgrade to Windows XP Professional. Customers licensed for use of Windows Vista Enterprise are licensed for Windows Vista Business and Windows Vista Business can be downgraded to Windows XP Professional.

Risk
Microsoft is warning that, after support is discontinued, users running Windows XP will risk unmitigated zero-day attacks because of reverse engineered security patches for newer Windows versions.

Market share
According to web analytics data generated by Net Applications, Windows XP is currently the second most-used OS with a market share of 28.98%. It has held the number two spot since July 2012.

According to web analytics data generated by StatOwl, Windows XP has a 27.82% market share as of November 2012, having dropped to second place in October 2011.

According to web analytics data generated by W3Schools, from September 2003 to July 2011, Windows XP was the most widely used operating system for accessing the w3schools website, which they claim is consistent with statistics from other websites. , Windows XP market share is at 13.5% after having peaked at 76.1% in January 2007.

License and media types
There are three main types of licenses for Windows XP Professional and Professional x64: Retail, Volume (VLK), and Original Equipment Manufacturer (OEM). Windows XP Home Edition is limited to Retail and OEM licenses, whereas Windows XP Media Center Edition and Windows XP Tablet PC Edition are exclusively available through VLK and OEM channels.

Each type of license has a different installation CD. For customized or retail media, there is a small difference on each type of disc that will allow that installation disc to accept only one type of product key.

Only retail and volume licenses include support for end-user installation scenarios from Microsoft. OEM software is preinstalled on systems and is supported by the system manufacturer rather than Microsoft. The price of such software is lower. There are two important restrictions on OEM licenses: Microsoft does not offer technical support, and the license cannot be transferred to another computer. The cost of OEM software products bundled with systems is not disclosed by Microsoft nor by its partners, as each system manufacturer will define its own bundling price.

Microsoft recommends that system manufacturers have their systems tested, for a fee, as part of the Windows Quality Online Services (Winqual) which includes extensive testing so that no component will cause instability in the Windows operating system due to incompatibility with the Windows operating system or with other system components or their respective drivers. Having a system tested and approved will allow the manufacturer to bear the "Certified for Windows" logo sticker on the exterior of the system, and there are additional benefits for having a tested product. This includes the products being listed on the Windows Marketplace. Because of the fees and extensive requirements, Microsoft acknowledges that smaller system manufacturers may not opt into the program until they produce computer systems at a modest rate and on recurring designs.

Retail
Retail licenses, those purchased from a retail store in complete packaging, are of two sub-types: "Upgrade" and "Full Purchase Product", often abbreviated by Microsoft as FPP. FPP licenses are transferable from one computer to another, provided the previous installation is removed from the old computer. Although upgrade licenses are also transferable, a user must have a previous version of Windows even on the new computer to which they are moving the installation. Retail licenses include installation support for end-users, provided directly by Microsoft.

Volume License
A Volume License is the license given to a software version sold to businesses under a direct purchase agreement with Microsoft, and is sold as an upgrade license only, meaning that a previous license must be available for each new volume license. Volume license versions of Windows XP use a Volume License Key (VLK), which is a product key that does not require product activation. The term "Volume License Key" refers to the ability to use one product key for multiple systems, depending on the type of agreement. Since Windows XP Volume License versions do not require product activation, this led to leaked copies of VLK media and product keys from businesses leading to piracy of Windows XP quickly spreading across the Internet upon early release. Beginning with Service Pack 1, Microsoft's active attempts to search out and blacklist known pirated VLK product keys became well known due to the inability to install the service pack on a system with one of the blacklisted keys. Later, this led to the Windows Genuine Advantage program.

Original Equipment Manufacturer (OEM)
Original equipment manufacturer (OEM) licenses are preinstalled on, and sold with, pre-assembled computers from system manufacturers. There are two types of OEM product types — those used for "direct OEMs" (major name brands that buy through a direct contract with Microsoft and produce and brand their own media from a Microsoft "Gold Master Copy" by using an authorized Microsoft duplication partner), and those used for "system builders" (local computer shops that buy generic, unbranded kits through authorized Microsoft distributors). Direct OEM product keys will often not activate with system builder installation media because direct OEMs are now required by Microsoft to pre-activate their copies in the factory using their own internal mechanism before delivery to the customer. It is recommended that system builders also pre-activate their systems before delivery, but this is not mandatory.

OEM installations can be customized using the Microsoft OEM Preinstallation Kit with branding, logos, additional applications, optional services, alternate applications for certain Windows components, Internet Explorer links, and various other customizations. All OEM customers must include support and contact information for the initial installation of Windows because it is the responsibility for the OEM to support the Windows installation, and is not provided by Microsoft to the end-user. Direct OEMs must create their own media, but have the option of creating their own custom recovery solution, which may or may not be similar to a generic installation. Direct OEMs may provide a recovery partition on the hard drive as the custom recovery solution rather than providing disc-based media with the computer.

Some end-users have found this to be a troublesome option, because in the event of an out-of-warranty hard drive failure, they may not have access to any installation media in order to reinstall Windows onto a new hard drive. System builders are not allowed the option to create a custom recovery CD/DVD media. The only deliverable media available for a system builder to give to the end-user is the unbranded OEM system builder hologram media kit. Because of this, when end-users reformat their hard drives and re-install from the installation media, they lose all the custom branding and support information that the system builder would have included.

As a supplemental recovery method to a CD/DVD-based installation, a system builder may employ a fully customized recovery solution on the hard drive. Whether utilizing a recovery partition or not, a system builder must still include the original generic OEM system builder hologram CD/DVD media kit. OEM licenses are not transferable from one computer to another. Every computer sold/resold with an OEM license must include all of the original installation media or recovery solution, documentation, Certificate of Authenticity, and product key sticker with the sale. Microsoft requires that all OEM system manufacturers include as part of the configuration the Windows Out-of-Box Experience (OOBE), which is the initial setup wizard encountered the first time Windows boots up. It is also required that value-added resellers (VAR's), retailers, and general resellers not tamper with the OEM's customized OOBE mechanism unless under permission by the OEM, and it is a recommended configuration for systems that are privately resold so that a customer will have a like-new computer experience upon first boot-up.

OEM licenses are to be installed by professional system manufacturers only. Under Microsoft's OEM License Agreement, they are not to be sold to end-users under any circumstance, and are to be preinstalled on a computer using the OEM Preinstallation Kit (OPK) before shipment to the customer, and must include at the very least the manufacturer's support contact information. They are, therefore, designed for installation only on a single computer and are not transferable, even if the original computer is no longer in use. This is not usually an issue for users who purchase new computer systems, because most pre-assembled systems are shipped with a preinstalled operating system. There are few circumstances where Microsoft will allow the transfer of an OEM license from one non-functioning system to another, but the OEM System Builder License Agreement (SBLA), as well as the OEM End User License Agreement (EULA) do not contain any allowance for this, so it is entirely up to Microsoft's discretion, depending on the situation.

Non-use by end user
In the event that end users decide that they do not wish to use a preinstalled version of Windows, Microsoft's software license agreement provides that the software may be returned to the OEM for a refund. Despite refusal of some manufacturers to honor the entitlement, it has been enforced by courts in some countries.