Thanks, Zyndstoff (aka Steven Gail).

Check your link. I Googled “Download the Avast-removal tool” to get

http://files.avast.com/files/eng/aswclear.exe

This time it was not the user’s decision / no action was required. I only clicked
upgrade program. After the requested reboot there was a dialog box asking for a
password to make any changes, a box I had never dealt with before.