I've moved XP installs from one PC to another. Sometimes used the excellent Hat Monster method. Other times, if it was moving from one fairly recent Intel chipset to another, I just cloned it, booted ...
After managing to completely hose my system, I decided it was time for a wipe 'n reload. I backed up all relevant files, and blew everything away. I'm installing Ubuntu 8.04 AMD64, and Windows XP 32 ...