These were serious infections. I didn't have time to benchmark, or to do anything fancy. I needed a cure. There was Symantec loaded on the machine. It identified the Backdoor virus, and said that it cleaned it out, but after a reboot it detected it again (and again and again). Symantec was impotent, even after I followed the removal instructions.
I then downloaded AntiSpyware. It told me after a scan that all I had was some tracking cookies, that were of low risk. I moved on.
The download was quick. It then updated the database and the scan was blazingly quick. It then completely cleaned the machine in one pass. I then tried it on another computer, and it found a virus in an ISO image that wasn't even activated yet.