Also try AVG for your anti-virus. There's only one pop up I've run into that it can't seem to get its claws on for some ungodly known reason and finds me about every three months.
SmitfraudFix, Vundofix, CCleaner, Ad-Aware... and Spybot S&D. For the experienced (meaning if you know what you're doing in your registry) try Hijackthis, SuperAntiSpyware, and Eusing Free Registry Cleaner.
I'd recommend SmitfraudFix and Vundofix as the TOP priority to download. Most trojans and maleware has a basis that translates over to one of those two programs. It'll find alot of stuff most EVERYTHING else misses. I seem to recall running into Zango before, to be honest.
Don't forget to run them all in safemode! :3
Worst comes to worse you guys post here:
http://forums.spybot.info/forumdisplay.php?f=22
They've helped me out alot and usually recommend running everything I just said, but if you're unsure how to handle Hijackthis post a log there and they'll run you through what's safe.