In 2001, Microsoft released Windows XP, which combined consumer and business versions of Windows and was built on the Windows NT core. It provided a more stable platform compared to Windows 98 and Windows Me, despite initial malware issues. Windows XP featured a vibrant blue interface, the iconic green Start button, and the recognizable "Bliss" wallpaper. It introduced customization options, including user-created themes, and tools like Stardock's WindowBlinds. Key features included System Restore, USB plug-and-play support, built-in CD burning, native ZIP file support, and Windows Movie Maker. Microsoft implemented an activation system to combat software piracy. Security measures improved significantly with the release of Windows XP Service Pack 2 in 2004, which introduced a default firewall and a Security Center. Windows XP became popular during the rise of the internet and supported applications like Mozilla Firefox, Google Chrome, and Skype. It left a lasting cultural impact, with many users expressing nostalgia for the operating system.