Make a new System Restore Point before continuing below - - -
boot into safe mode (F8)
start->run->CMD
enter CHKDSK C: /R
if this is a laptop, be sure you can run while
connected to the A/C, as this puppy will take >1hr to complete.
the normal CHKDSK /F runs three sections, /R runs FIVE sections and is very thorough.
the /R should remap any bad sector(s) and attempts to recover data so remapped.