You have a trojan and a adwise infection-it happened to me and eventually it shut my computer down. It cost me $400.00 for Geek Squad to come out and fix it. Most likly you downloaded music off of lime wire or a free music site-right? if not you down loaded something that was infected. The worst thing you can do now is open the page you are redirected to. Are they asking you to purchase their program to clean your computer of virus'? if so DO NOT DO IT, they are the ones who paid someone to infect you computer.
Or you can pretend I'm Geek Squad and I can help you fix your computer tomorrow for free. Right now I have to go to bed. PM me your AIM so we can talk on there tomorrow.