If you don't have an infection that prevents you from installing another AV program, I would try avast! Fully update it, then run a boot time scan. It will preempt the loading of any and all programs (including most of the OS), allowing you to detect the malware before it can stealth itself. That should enable you to clean out all of the stuff.
Couple of things though: The boot time scan won't work under 64 bit OSes, so if you have one, this won't work for you. Also, if you start detecting system files that are infected, leave them alone, stop the scan, and start backing stuff up. The only effective way to treat it now is a reformat. And if you detect a rootkit, God help you.