To those who replies, my thanks.
1. As soon as I got home, I woke the computer, and received an Alert from Super AntiSpyware, which was rather strange, as I had turned SAS off just before posting my original message here, so that I could see various taskbar and Firefox icons.
2. I started SAS, and seeing that it had just updated its data base, I ran a quick scan, which came back clean.
3. I did not think to check the SAS forum, as I so rarely go there. Thanks to the link provided in this thread, I read the posts, including that from SAS apologizing for the foul-up.
4. After I reinstall Avast! on the 32-bit computer, assuming that it will now install and run correctly with the update to SAS, that will give me some time to see if I can find out if the world did end. I rather hope not, as the time spent fighting with SAS/Avast! earlier today would then have been in vain.