If WinXP has an aneurism during re-installation and defaults to the Blue Screen of Death, with the dreaded error 000021a and the mysteriously simple descriptor: “Unknown Hard”, slap the monitor and the keyboard around a few times (I’ll give you hard, bitch!) and kick the minitower around until you smell smoke.
Alternatively, insert the WinXP install CD again and set the boot order in BIOS to optical drive first, hard drive second, then reboot and try, try again.
Bill Gates can be a real asshole sometimes.