If you plan on installing WindowsXP SP2 on a computer with a Prescott CPU this Windows XP critical update is for you. Under certain circumstances your system could hang during installation so patch your rig before upgrading.

This non-security critical update helps resolve an issue where a limited number of systems running a BIOS without production support for Intel Pentium 4 and Intel Celeron D processors based on Prescott C-0 stepping can potentially hang on Windows XP Service Pack 2 installation. After you install this update, you may have to restart your computer.


Source : HardOcp