When next I plugged the "problem" disk back on and used the Microsoft account password I got in with no problems and there was Avast Uninstall program waiting for me to finish installing it. Since I never needed it in the first place I discontinued the AvastClean install.
Similar to using an extension cord that's plugged into a dead socket and wondering why the lamp doesn't light.
Even replacing the light bulb didn't work. :)
Glad to hear you problem is finally solved. :)
You should now have gained enough knowledge to help some other less knowledgeable folks. :)