[Matt D.]

Run chkdsk /r and let it go until its done. If it won't boot after that you're stuck with attaching the drive to a working computer to recover files off of it (if you need to), format it and reinstall the OS.

I just ran into this at work. chkdsk didn't do jack shit so I was stuck with recovering the files and returning the drive to IBM under warranty. I ran a different drive repair tool on it and it ended up locking up part way through. Ran IBM's onboard drive scanning tool and it threw an error right away. If you value this computer's reliability I would throw the drive in the trash or at least not store data on it that you care about.