ClamWin has an awful reputation from what I've seen, and probably deserved. However, the Linux version (deployed from a live CD) may be decent for second opinions IMO. Today I got to see it detect the CompuTrace commercial rootkit by heuristics. Most of the AVs on VirusTotal fail to flag that one, by either signatures or heuristic detection. I wouldn't trust it as my only tool (but then I wouldn't trust anything as my only tool). Still, it might be handy for finding likely malicious files. I would just suggest not enabling PUA detection first thing, because that will flag every packed binary on your system (and there are a lot of those on a typical Windows install). Anyway just thought I'd put that out there; especially given the state of most commercial AV live CDs.