Perhaps try running a disk check (chkdsk) over your C drive (or whichever drive your content files are installed on).
Windows 7 instructions in the following document: How to use CHKDSK (Check Disk)
Select both Automatically fix file system errors and Scan for and attempt recovery of bad sectors, or use chkdsk /r (depending on which way you decide to go about doing this). You'll almost certainly have to schedule the chkdsk to run on startup. The scan should take quite a while (especially if it's on the C:\) ... if it quits after a few minutes or seconds, something's interfering with the scan.
Does the chkdsk find/repair any damage? If so, can you delete the corrupted files now?