Thank you. Malwarebytes Anti-Malware allowed skipmagee to download the latest virus databases and get her virus protection working again. It also found other viruses on my computer. My AVG is still out of commission, but I was able to install a free 30-day trial of TrendMicro in the interim.

DrWeb found another trojan, gtdownlr_134.ocx, that I've probably had for a while.