HiJackThis
A free utility that finds malware and other threats
... capabilities, HijackThis comes with several useful tools to manually remove malware from your computer. However, HijackThis does not make value based calls between what is considered good or bad. It is important to exercise caution and avoid making changes to your computer settings, unless you have expert knowledge. Source code is available SourceForge, under Code and also as a zip file under Files.