Avast backed up with these 2 FREE utilities is all you need......
http://download.cnet.com/Malwarebytes-Anti-Malware/3000-8022_4-10804572.html
http://download.cnet.com/SuperAntiSpyware-Free-Edition/3000-8022_4-10523889.html
Malwarebytes anti-malware along with Super anti-spyware will catch what Avast misses....all products should be backed up with these...no matter what you have.....