Originally Posted by MY REXTC

If you're running on XP, boot with the XP setup cd and choose the option to Repair installation, when in the XP Recovery Console, run CHKDSK and if it's nothing major it'll find any fix any bad sectors on ur hdd, but could also be video card on motherboard.

If the chkdsk option doesnt work, see if you can borrow a video card from someone and if that doesnt fix it, reformat.

My 2 cents,
Josh