My computer was being bad a while ago, so I took it into Best Buy (it's a laptop) and they had me run a program that came with the computer. I think it's called a system restore. What it does is completely erase everything except for what was on it when you bough tit. Giant pain in the butt, but problem solved. You should ask an expert about it before you do that though. Make sure anything you have saved in the memory is saved to disk. I think it erases the hard drive or the c drive, but ASK AN EXPERT! This just worked for me!