Download SpyBot: Search and Destroy.
http://www.safer-networking.org/
It does a lot more than AdAware and gets rid of most of those annoying trojans too. (Be sure to update it before you run it though).
Reboot and if you still have trouble try running HijackThis,
http://www.tomcoyote.org/hjt/ , and sending the log file it creates to a support forum. (or paste it here and I'll look at it but I'm not the best choice) Though SpyBot is pretty hardcore and should take care of the problem.