DavidR,
Thank you for the prompt reply.
I had the previous ais file, so I cleared the disabled version and reinstalled, then updated.
It is now working.
I had thought there would be a way to do this this without a reinstall. Being this is the second time this year that a false internet scanner has bumped Avast, I should perhaps purchase an active malware blocker.
Again, thank you for your help,
david