fwiw, in case this helps some

went and retried to boot from the orig OS drive that i had installed the new copy of Win 7 Ultimate on, just to reread the error msg - indication was hardware or firmware has been changed, yada yada about going to BIOS and selecting another secure drive.

Keep in mind, during installation win 7 ultimate hard restarted successfully 7 or 8 times, then during installation of each program (about 12) i always do a restart, then during the windows updates downloads, depending on the type of update and size, i might download 2 or 3 updates, up to 30 or more (security or defender small updates, and most had required restarting, i'll estimate somewhere between 12-15 restarts, all successful. It wasn't until i had 2 or 3 updates remaining, when the last update failed to restart.

I opened the windows file (C:Windows folder and replaced the entire Boot folder with the one from the Win 7 Home Premium drive. Win 7 Ultimate drive booted and i've finished downloading updates and tweeking programs etc

big relief not to have to go thru a full new re-install

again, fwiw