MalwareBytes anti-malware and SuperAntiSpyware both have free versions that are good to scan with and remove malware. The free versions are for scanning only and provide no real time protection.

http://www.malwarebytes.org/

http://www.superantispyware.com/

I also would not install two anti-virus (AVG and Avast) applications on your computer at the same time. Keep whatever your normal anti-virus is and if you want a 2nd opinion use an online scanner. The ESET (NOD32) online scanner seems to be good.

http://www.eset.com/onlinescan/

Or you could use Trend Micro HouseCall online scan.

http://housecall.trendmicro.com/