Upon scanning a very popular mobile Android rooting program, SuperOneClick, that was downloaded to my PC with Avast the results showed no virus. But after installing the program and then running a boot-time scan, several viruses showed up and were cleared by Avast.
The good: Boot-scan fixed the problem
The bad: If I hadn't run a boot-scan the virus would have thrived
The ugly: Avast should have detected the virus when I scanned it in the first place.