Windows XP removed support for PC-98, i486, and SGI Visual Workstation 320 and 540, and will only run on 32-bit x86 CPUs and devices that use BIOS firmware.

In January 2000, shortly prior to the official 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", named after Whistler, British Columbia, as many Microsoft employees skied at the Whistler-Blackcomb ski resort.

Subsequent builds gradually introduced features that users of the release version of Windows XP would recognize, such as Internet Explorer 6.0, the Microsoft Product Activation system, and the Bliss desktop background.

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

Microsoft had originally planned to use the slogan "Prepare to Fly", but it was replaced because of sensitivity issues in the wake of the September 11 attacks.

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 decorated helicopters.

XP also added ClearType, a new subpixel rendering system designed to improve the appearance of fonts on liquid-crystal displays.

[30] To enable running software that targets or locks out specific versions of Windows, "Compatibility mode" was added.

Unlike with Windows XP, however, it was hidden from the operating system as it was not enabled by default and had to be manually activated through the Register Server utility.

[54] Two specialized variants of XP were introduced in 2002 for certain types of hardware, exclusively through OEM channels as pre-loaded software.

[59] In 2006, Microsoft also unveiled the FlexGo initiative, which would also target emerging markets with subsidized PCs on a pre-paid, subscription basis.

[60] As a result of unfair competition lawsuits in Europe and South Korea, which both alleged that Microsoft had improperly leveraged its status in the PC market to favor its own bundled software, Microsoft was ordered to release special editions of XP in these markets that excluded certain applications.

[63] The "K" and "KN" editions of Windows XP were released in August 2006, and are only available in English and Korean, and also contain links to third-party instant messenger and media player software.

Headed by former computer hacker Window Snyder,[74][75] the service pack's security improvements (codenamed "Springboard",[76] as these features were intended to underpin additional changes in Longhorn) included a major revision to the included firewall (renamed Windows Firewall, and now enabled by default), and an update to Data Execution Prevention, which gained hardware support in the NX bit that can stop some forms of buffer overflow attacks.

Raw socket support is removed (which supposedly limits the damage done by zombie machines) and the Windows Messenger service (which had been abused to cause pop-up advertisements to be displayed as system messages without a web browser or any additional software) became disabled by default.

[79] In September 2007, another minor revision known as SP2c was released for XP Professional, extending the number of available product keys for the operating system to "support the continued availability of Windows XP Professional through the scheduled system builder channel end-of-life (EOL) date of January 31, 2009.

[114] However, an exception was announced on April 3, 2008, for OEMs producing what it defined as "ultra low-cost personal computers", particularly netbooks, until one year after the availability of Windows 7 on October 22, 2009.

Analysts felt that the move was primarily intended to compete against Linux-based netbooks, although Microsoft's Kevin Hutz stated that the decision was due to apparent market demand for low-end computers with Windows.

[116] These updates, while intended for the embedded editions, could also be downloaded on standard Windows XP with a registry hack, which enabled unofficial patches until April 2019.

[126] The government also had concerns that the impending end of support could affect their anti-piracy initiatives with Microsoft, as users would simply pirate newer versions rather than purchasing them legally.

[127] Several governments, in particular those of the Netherlands and the United Kingdom, elected to negotiate "Custom Support" plans with Microsoft for their continued, internal use of Windows XP; the British government's deal lasted for a year, and also covered support for Office 2003 (which reached end-of-life the same day) and cost £5.5 million.

[133] Microsoft continued to provide Security Essentials virus definitions and updates for its Malicious Software Removal Tool (MSRT) for XP until July 14, 2015.

[134] As the end of extended support approached, Microsoft began to increasingly urge XP customers to migrate to newer versions such as Windows 7 or 8 in the interest of security, suggesting that attackers could reverse engineer security patches for newer versions of Windows and use them to target equivalent vulnerabilities in XP.

For this reason, manufacturers often did not allow any updates to devices' operating systems, leaving them open to security exploits and malware.

[138] Despite the end of support of the main version, Microsoft has released three emergency security updates for the operating system to patch major security vulnerabilities: Researchers reported in August 2019 that Windows 10 users may be at risk for "critical" system compromise because of design flaws of hardware device drivers from multiple providers.

[154] Blizzard Entertainment ended support for World of Warcraft, StarCraft II, Diablo III, Hearthstone, and Heroes of the Storm on Windows XP and Vista in October 2017.

CNET described the operating system as being "worth the hype", considering the new interface to be "spiffier" and more intuitive than previous versions, but feeling that it may "annoy" experienced users with its "hand-holding".

They panned Windows XP's new licensing model and product activation system, considering it to be a "slightly annoying roadblock", but acknowledged Microsoft's intent for the changes.

[158] PC Magazine provided similar praise, although noting that a number of its online features were designed to promote Microsoft-owned services, and that aside from quicker boot times, XP's overall performance showed little difference over Windows 2000.

Windows XP's longevity was viewed as testament to its stability and Microsoft's successful attempts to keep it up to date, but also as an indictment of its direct successor's perceived failings.