I have a laptop that got infected and it would not let me do anything to remove it. I could still use IE but could not restore, install or remove anything. I was about to give up and buy a new one and Microsofts automatic update just happened to run. To my amazement it started working again and the problem was gone. I assume something with their malicious software update took care of it.
http://www.macecraft.com/jv16powertools2009/
You can also try this. I had a problem with my desktop and when searching I found this. Was highly recommended. And worked great. Free 30 day trial.
Also Ad aware
http://www.lavasoft.com/products/ad_aware_free.php
and spybot search and destroy
http://www.safer-networking.org/en/home/index.html