Another possible solution to uncompress every compressed file on the drive:
Open a command line window (Start >> Run >> type in "cmd" then enter).
Navigate to the root of your hard drive using
.
Then, type in
This sets the uncompress (/U) action on all subdirectories/files (/S) on the drive, and continues even when errors are encountered (/I). This should uncompress everything on the drive that's compressed, and will take a while depending on the size of the drive.
Good luck!