Thank you DavidR for the suggestion. I unistalled Avast, rebooted, ran aswclear program, rebooted, new install of Avast, rebooted, boot file and startup file check, inserted license, Avast updated virus database and then, sadly, the license expiration pop-up window re-emerges. On the positive side, Avast still has 2524 days left on the license according to the program. I bought this license on-line through Ebay in what seemed to be a reputable manner. I wonder if I have been had.
Respectfully.