You can do a reinstall that will do whats called an "Old Files" to save your data:
Thats probably the best way to do it. Otherwise you can insert the dick, boot to it and run a repair. Open the command console then type 'C:' and press enter.
It will change to C:\. Then type in chkdsk /f/r and let it run.
But the first option will probably be the better one to go with.