I did try Kevin's suggestion and reset to default. That did help somewhat. I still get the small pop-up windows for anything I want edit.
However, now, the procedure is this:
1) open edit person
2) click on the fact to be changed
3) click either Sources or Notes in the Details screen
4) click Edit and the little pop-up appears
5) click pop-up to open full screen
6) click Edit and Edit is now working!!!!!
So, thank you Kevin for the improvement.
Surely, I'm happy that now I can make changes.....but every time I do, it takes at least 6-8 clicks to do what used to get done with 3 or 4 clicks.
To answer Tom...it was all those things.....it was as if Edit had been put in the freezer!!