Thanks. CTRL+ALT+DEL didn't work. If I "wait" will the cursor eventually unfreeze?

Entire computer keyboard is locked. How do I unlock? Can someone help, please?

It may and it may not respond on it's own. I took it that the application had 'frozen' or locked up, after your comment, I wonder if you have inadvertently pressed something to disable your keyboard.

Is it an external USB keyboard or is this a laptop keyboard? Are you posting from the same computer?

The computer as I had a saved copy of the document I'm sure you're correct inasmuch as I must have inadvertently hit something on the keyboard. External keyboard. And no, I couldn't use the computer to ask for assistance while I was waiting for advice. Am using iPad for this discussion. Thanks so much for responding so quickly as I was about to pitch the whole bloody system into the swimmimg hole!

Still curious how to unlock the keyboard as these old hands aren't as nimble as they once were and I could have easily caused the problem. (The shaky fingers issue is the reason I use an external keyboard. Can't begin to use the laptop keyboard anymore.)

If you have a saved copy of the document, just press and hold the power button until the computer goes off. On starting up again, it should be fine. What sort of document is it? Word? Adobe Reader?

Worked beautifully! Let's hear it for "saving"!!! Thanks for your great help and patience.

It is Microsoft 10 Word, on a new Acer computer with newly installed Windows 10.

It was probably nothing you accidentally did. Sometimes computers just freeze up: it could be that the program you are using is acting up, or another program or process going on in the background has an issue, or there was a slight momentary variation in the power supply voltage, or a dozen other things. If you wait for a minute or two and it doesn't unfreeze, then waiting any longer is probably not going to do anything. That's why it is good to make sure the autosave function in a word processing program is set up to save every couple of minutes. It won't slow you down while you are working, and that way you won't lose very much if the computer freezes up, and you can just re-boot the computer and get functional again.

Many thanks to PKponder and Kudzu for your help and kindness. You got me through this craziness. Final document a done deal, thanks to you both!