As iq_132 said, SP3 should hopefully resolve any problems. If not, you don't have to reformat to repair Windows. You could try using the Repair function built into the XP CD. Boot from it and let it run as if you were going to re-install Windows but instead choose to repair your existing installation. It should be pretty easy to find, I think it says press F3 to repair, something like that. Whether or not that fixes your specific problem I don't know, but it won't affect your existing installed apps etc, worth a shot. Good luck!