OK, I lost the password for the program itself, so I can’t make changes in my setup, or install new software. (Changes to computer blocked until I call off the dogs.) Is there a workaround or bypass?
Doug
Please (re)search before posting.
As has been explained many times already, you need to perform a clean installation.
Here’s the link to help you perform a clean install. 
Clean Install of Avast:
https://goo.gl/4Ptzkf