Besides the fact that it is free AVG is junk. Not really worth having IMO. I have uninstalled it from all my rigs. False positives (which tortured my system. thanks AVG) and numerous misses have pretty much killed any confidence I had it AVG as a legitimate A/V alternative. I like free but I like a decent product as well.
I'd second Ad-Aware and any other free spyware app you can find. They all miss some. Nature of the beast. Spybot does the best job of the lot IMO but i have multiple spyware programs since there are occasions where spybot will not solve the problem. Rare but it happens.