ETA:TL;DR: My solution, seen below, did not work.
I did those things you suggested, but no joy. That Magician software is very nice, by the way; thanks for that.
I may have found the solution. When I looked at the drive in device manager, it showed the drive was using the MS driver from June of 2006. If I tried to update it, it told me that that is the current driver.
Then if I scanned for hardware changes when the D: drive was not showing in device driver, the drive would connect or show what the drive is (HGST HTS721010A9E630 ATA), a warning would pop up. Upon reading the troubleshooter it said something about a driver by >>EgisTec<< failing to do its thing. :/
So I set Windows update to auto, deleted the hard drive's driver, and allowed the restart. Now in device manager the drive's name (as above) is shown.
Lest the drive is failing, I backed it up, and shopped for it online--roughly $60.
Thank you very much.
Regards,
I9