Thank you for the reply. Unfortunately entering the key is not the issue.
I entered a key about a month ago. When I go to the About screen, I can see the key number. Avast! took the number with no problem.
When I reboot, I get a red pop-up that says "The Program Trial Period will end soon. Click here to remedy this...". The message is similar to the updated database/program pop-up. When I click on it I get large dialog box titled "Avast! Licensing" that says "To continue to protect your system from the lastest threats, you will need to obtain and insert a valid license key." then "Please choose an action to take:" My options are to obtain a key or upgrade, or Remind me later. There is no option to say it is already registered.
I hope this information is more helpful.