Try A-Squared. It has got rid of more hard to shift things on computers i've been repairing, then any of the others. It is free as well. Spybot comes in at a close second.
To do the repair you need to get windows started in Safe Mode without networking. Be sure to disable networking asap, as the infection could be logging your bank details, etc, and sending them to someone.
If you are going to look at dodgy sites, dont do it with IE. Firefox with noscript installed is the best way to browse any site. Then you get to choose if you want to allow javascript and plugins like flash.
Links.
a-squared Free (formerly a² free) Freeware! A2 is a free of charge Anti-Trojan, Anti-Worm, Anti-Dialer and Anti-Spyware Software - optimal protection The home of Spybot-S&D!
Also if you are considering buying an Antivirus/AntiSpyware/NetSec App, then look at Eset's Smart Security Home Edition. Its what i recommend to people who are buying packages. It has a good reputation, and it doesnt eat resources like Mcafee/Norton.
Virus Protection Software from ESET NOD32 - Wikipedia, the free encyclopedia