I just found Microsoft Security Essentials (free at http://www.microsoft.com/security_essentials/support.aspx?mkt=en-us ) and it finds stuff scans with McAfee, Lavasoft AdAware, and Malwarebytes all missed.

There is a bad one going around called ALUREON.H or TDSS that really slows things down and messes with redirecting sites. Only the Security Essentials both found and removed it.

Also, I'm not real computer literate so I subscribe to the Kim Komando newsletter, use her website and occasionally catch her radio show for all kinds of computer advice explained in plain language. http://www.komando.com/