Format Baby! Format

It it were me, and my machine, I would format that puppy, (quick) the whole disk, and install Windows 7 on it, because of the plain simple fact that Windows 7 is a proven, reliable, ready to go, familiar to operate OS. I mean, there are lot's of people still running Windows Xp, because it is a proven and well liked OS. That is what I would do. Just make sure you have a good legit Windows 7 disk, and re-install to your hearts content!