I have just had the same problems with a Vista Home laptop - nothing seemed to solve the problem, no chkdsk or defrag. Or a forced chkdsk said it was a RAW drive not NTFS. Booted from UBCD4win ran a disk check and found a few errors, but still the same problem when I ran Vista. MBAM wouldn't run, so I suspected a virus infection or some other issue. Ran SuperAntiSpyware from the UBCD4win disk - detected a variety of nasties. Reboot and guess what, Vista runs chkdsk on boot. Hope this helps someone, I hate having to reformat, etc, especially on a customers computer. Regards Jeremy