Disk Error

Greetings

I am running a Windows XP Pro PC, after returning to my desk yesterday, the only thing on the screen was “disk error” press any button to restart. Everytime I restart that kept coming up, after booting to a win98 startup disk I can see the contents on the drive but can not access the windows directory. When I try to do a dir windows command it comes back with “Data error reading drive c” abort, retry, fail

I can do a dir command for anyother directory on the computer except windows

Thanks in advance

Matt