Well, I solved the problem (indirectly). After spending an entire day trying different fixes, including chkdsk /r and even running my restore image program from DOS, nothing worked so I ended up disconnecting the C: drive and connecting a spare hard drive as Master on which I did a fresh install of XP, then I reconnected the corrupted "C:" drive as Slave and ran the restore program from the "Master" drive in Windows (not DOS) and then switched the C: drive back to Master, rebooted and everything was back to normal. I have NO idea what happened but this solution worked, especially since I had just created a backup image a week ago. When all else fails... do a restore. If this were to happen again, I would just skip the whole repair and just do a restore. Less of a headache!