I agree that using a free backup program like Paragon Backup & Recovery 2011 (Advanced) Free
instead is a good alternative.
If you really wanted to try and fix it, then....
You might see if running a sfc /scannow
command may be able fix this for you.
If not, then as a test, create a new Administrator account and see if it works while logged in this new account instead.
If not, then you could try doing a system restore
using a restore point dated before you started getting this error (if known or best guess)