OK. This is what I found:
The command 'bcdedit|find "osdevice"' found nothing. This is a dual boot drive (Win 7 and Win 10, with another partition once intended for Ubuntu (but not currently used).
To simplify things, I created empty folders in the root directories of each of the OS's labeling them: "1 - This is Win 7", and on the other "1 - This is Win 10". Using the number one ahead of the description tended to list these empty directories toward the top of the list for that drive.
With that done, and booting to the command prompt from the Win 10 DVD, I ran the sfc /scannow /offbootdir=d:\ /offwindir=d:\Windows where the d: drive was, indeed, the Win 10 drive.
After a while, it produced this response:
"Windows Resource Protection found corrupt files but was unable to fix some of them. Details are included in the CBS log windir\Logs\CBS\CBS.log. For example C:\Windows\Logs\CBS\CBS.log. Note that logging is currently not supported in offline servicing scenarios.
When I looked at that log, it listed a LOT of items that were not fixed.
Correct me if I am wrong, but it is seeming more prudent to wipe the partition, and reload Windows 10 - and bite the bullet about re-installing all of the apps currently loaded.
Any thoughts? Again, my thanks for your assistance.