Yeah, either hardware issues or there's something really screwy in the windows registry. If you can and want to, as I would, I would take out each part and see what the problem is, like taking out the hd and replace with a different one, etc. But that's just me. I would just format the hd and reinstall windows as Kage said too.
Macbook Pro and Logitech z5500s. All you really need.