Well, I finally was able to get my license file to work I've got
the app Graphic Converter. My Avast license file, which I kept in my Documents folder got formatted
into a Graphic Converter medium and, for some reason, couldn't be accepted or acknowledged by Avast.
I was able to get the license file to open in another medium. For some
reason, VLC Media player, which automatically became the Avast file and other files medium (by default, I guess) once I got Graphic Converter out of the way, could acknowledge my license file and Avast has now accepted it. Why VLC Media Player? I haven't a clue. But
all's well now. Hopefully, my Avast license will give me no more trouble
from now on.