Had to revert to a Restore Point, and it worked fairly well.
But, quite a few Folders that I had on my Desktop did not reappear.
I had them backed up to a memory stick, luckily, and tried Copying them to my Desktop from that.
Interesting: on just about all of them, I got the message that the Folder already exists (on the Desktop) and do I want to Replace, Combine...etc.
But, the icons for them are not on the Desktop.
I did a "Refresh" of the Desktop, but that didn't help.
How come no icons ?
How can I make the icons re-appear ?