have you tried to upgrade your video driver for xp?
Also make sure you get all the xp critical updates, at least service pack 1 and the other 70 critical updates with it.
I've reinstalled XP Pro on my computer four times in the last month because every so often it fails to boot (even in safe mode or last good configuration, both of which freeze during bootup) and I end up using a WinME boot disk to install WinME so I can then run my XP upgrade installation. Even after the reinstallation, XP complains that system files have been replaced by unrecognized versions (and needs the XP disc) so often that I leave my XP CD in the drive at all times.
What could be the underlying problem? It's a 2 yr. old Dell Dimension 4300 P4 1.4 GHz, with a secondary internal hard drive, the CD-ROM has been replaced with a DVD-RW, aside from the parallel port laser printer, no other hardware. I've defragged, virus scanned, and anti-spywared my computer often.