Microsoft Windows XP Service Pack 2 (SP2) provides new proactive security technologies for Windows XP to better defend against viruses, worms, and hackers. In addition to a more robust security infrastructure, SP2 improves the security configuration options of Windows XP and provides better security information to help users faced with security decisions.
View: Release notes
View: List of security updates
View: List of fixes
Download XP SP2: Express Install | Network Install
NOTE: the Network Install option is recommended if you want to backup the complete Service Pack for future installations, i.e following a reformat.