Cyclical redundancy check? Just saw that one today trying to copy files
from a burned CD. The CD won't even run an install. Bad media, indeed.

Did you run chkdsk? Try running "chkdsk /r c:" from a command prompt.
You'll be prompted to run it on a reboot. Hit "Y" and then reboot. Then
watch it. It will tell you how many bad sectors you've got. The fact you
can't run the OEM's diags is not a good sign.

Nihil's right: start backing up your data.