Hello all,
Today I have tried some further possible solutions and seemingly found a solution/workaround.
I tried setting the Free Avast software to passive mode and then reset the computer.
That definitely occurred as Windows10 alerted me to the fact that neither windows or Avast antivirus was enabled.
However I could not get the Avast software to update and remove the expired license indication.
While it was in passive mode I also tried to copy the license file from my wifes computer but again even with Administrator permission it was blocked.
A workaround:
What I have now done is to
(a) uninstall the Avast free antivirus software, then
(b) I could copy over the license file from my wife's computer (the relevant Avast Software folder are left in place), and
(c) re-installed the Avast free antivirus software.
Lo and behold, the license file was not removed and the re-installed avast free antivirus software now indicates my Avast subscription/license is valid.
From the taskbar, right clicking the "Registration Information" indicates the subscriptions on this PC as:
Avast Free Antivirus <active>
Expires August 22, 2021 (366 days left)
So while not optimal, I have seemingly worked out how to restore active/registered version.
Luckily, I had access to another PC with the free avast antivirus software from which to copy the license file.