If you have a Windows Vista Disc (not a recovery disc)...
Insert your Windows Vista DVD and follow the stages here .
When you reach this screen, choose Command Prompt

In the command prompt type chkdsk c: /r and then press Enter
If you don't have the disc...
To run a Chkdsk from the System Recovery Options, go through the following...
- Power on your PC and keep pressing the F8 key
- The Advanced Boot Options screen should appear and you should be presented with various options.
- Use the arrow keys to highlight Repair your computer, and then press ENTER. (If Repair your computer is not listed as an option, then your computer does not include Startup Repair as a preinstalled recovery option and you will need a Vista Installation disc)
- Select a keyboard layout, and then click Next.
- If prompted, select a user name and enter the password, and then click OK.
- On the System Recovery Options menu (see picture below), click Command Prompt and try running chkdsk /r c:

If the chkdsk does not find any problems, try restoring the PC back a few days.
Either boot from the Vista disc or use the F8 method above and when you get to the screen as shown above, choose System Restore. Go through the next few steps and select a date before this problem occurred.
Let me know how you get on
