So, by way of an update: I did download the free version of Avast! last night -- about 2 hours via dialup (not sure exactly -- I took a nap during the second half).

It offered me more options during setup than AVG used to. For some of them, like the address of my ISP's mail server, I was worried about the right answer and was ready to enter my best guess when I discovered that one of the pulldown choices already showed my best guess. It turned out to work OK in the end.

When I clicked on the link to apply for the activation key, it opened in IE (5) even though I rarely use anything but Firefox. I filled in the info and clicked Submit -- and IE immediately crashed. I started to apply again, this time typing the address into Firefox, but before I got very far into the form the key arrived in my e-mail. Apparently IE had crashed right after submitting my request.

As I recall, AVG had pretty much insisted that I update the virus database right away. Avast! didn't insist, so I fell back on my AVG experience and did it anyway.

Yesterday, right after installing, when I tried sending test messages back and forth between two e-mail accounts there was no sign that they were getting scanned by Avast!. I tried it again today; the Avast! e-mail scanner icon appeared in the System Tray and all the right signs are in the message header. I think I have a working anti-virus again!

I went to Windows Control Panel and uninstalled AVG. There are only some small traces of it left in the Registry, not enough to bother about.