@PilgrimHiker,
Thanks to all!
As I've been futzing around attempting sort this out, I decided (for whatever reason I have no idea) to take a look at Webshots, which I have loaded on as my wallpaper function . . . and as I poked around in there, guess what I found? In addition to my most favorite pix, I had at some moment lost back in the mists of computer time checked the box "Display calendar on Desktop" . . . where it had been obediently sitting with the little date highlight jumping from number to number through all those weary days of my life . . . until Windows 10 came along, and Webshots got its back up and said "I'm freezing!".
So, a simple, mere unchecking of a box has removed the offending used-to-work calendar from view, and All Of Life Is Now Good!
Appreciate y'all helping sort this out.
END OF STORY.