probably gonna have to reformatt your hard drive, does it hve this built in feature? (if it does, you'll know abou tit) otherwise you'll need to contact the people who made your computer (hp, compaq, sony, and so on) and ask them for the resintall disk... once you have them, you will lose everything, it will be like your co mputer is brand fucking new, just as you bought it, so save anything you need to keep...