Perform a clean installation of avast.
See reply #3
This obviously didn't work for other users, but I will give it a try once I have time to waste on it. I will report back when I can.
Thanks for your help.
EDIT/ADDENDUM
Waiting till I had time didn't work out, as after closing my browser, and trying to open DreamWeaver (the work I had to do), none of my programs would open at all. I couldn't even get back in to Firefox to return here. I wound up having to do a reboot to safe mode, uninstalled Avast, and did the clean reinstall as suggested. So far, this worked -- I can get/send mail normally again, and my programs are opening. However, after yesterday's update to the newer version of Avast, all was well until a reboot. If the same happens again, I'll be back.
Again, thank you very much for your assistance.
I hope the original poster has found help for their situation, as well.