It took two full evenings; but our computer is back to normal now after installing the most recent group of Windows Updates. It should not have been nearly so hard to resolve the issue. I understand that the software which runs a desktop PC is complicated. But that just means there should be more testing rather than less. I even tried “Upgrading” Windows. But that failed without completing too. (AFTER grinding away for a couple of hours.) I’m not confused or intimidated by technology, so I wasn’t stumped. But I still don’t like wasting hours fixing something that I shouldn’t have had to do in the first place.