[CarrotAndStick]

AVG finds tons of spooky stuff that Norton used to routinely miss. That made me do the switch. It may have its holes, but for a decent AV that's also free, it does a good job.

AVG is bad at spyware/trojans though. NoSpyware was used once to remove a rather persistant trojan that AVG simply failed to detect.

[jdm]

Or try SuperAntiSpyware. That's a really good one too. It will clean and fix many things that you otherwise need a specific utility (like SmitFraudFix, Vundofix, Fixwareout, etc.) to permanently clean.