Thanks, Tones. The conditions under which I operate seem to make my system relatively unattractive to viruses. Historically, I've had much more trouble with antivirus software crashing the system, raising false alarms and deleting apparently innocent files than I've ever had with the viruses themselves.

Picture this: I used to save text from online news articles in a file called TEMP.TXT, then run a DOS program called NED.COM to reformat the text quickly for printing. The desktop icon for the latter was titled "Ned temp.txt" and stored in a file called (Windows long filename) "Ned temp.txt.pif". The first version of AVG that I used, immediately identified "Ned temp.txt.pif" as probably infected because of the double extension. I changed the icon title to "Ned temp txt" (no period) and had no further problems.