[GMScud]

Sounds to me like you ended up with Security Tool. It's a pesky f**ker. I had it before. Same exact symptoms. IE didn't work, I could surf through firefox, but the virus pretended to be anti-spyware software, all the while drastically bogging down my system. I think it comes in trojan horse style. I ended up deleting some individual registry items that it planted in my computer, and AVG anti-virus ended up cleaning up the rest. Google "security tool" and you'll find some removal tips.