Nasty trojan! HELP!

I was stupid enough to click a link from a complete stranger and now my computer is bugged. It seems the only serious thing it does is disable my anit-virus software. I've tried with AVG, Microsoft Security Essentials and Kaspersky PURE, but none of them can beat the little bastard. Can anybody give me any advice? Perhaps some nice anti-virus software? Or is formatting the only option? :( I wouldn't want that, since I don't have the disk with my system.

I like Malwarebytes.

Do you have a friend with a hard drive -> usb device? you can just run a virus scan off it on their computer and it will clean your computer out in one scan.

that is the easiest option. Failing that, what happens if you run avg in 'safe mode' ? it will reboot the computer and run in a shell interface (prior to windows)