Robert in CA wrote:

I think I understand,... were actually going after the
registration key for Windows 10 without actually installing
Win 10. Is that correct? Then at a later date I can install
Win 10 side by side with Win 7 so I can continue to use Win 7
but can also use Win 10 if I choose. Do I have that right?

I do have a spare drive so that's not a problem. I will have to
re-read your instructions on how to do this. True, I have done
repairs before but only with your guidance and help. I need to
take this slowly so I understand what I'm doing and not mess
anything up.

Robert

Because this effort is largely "throwaway",
that's why I suggested cloning the existing C:
drive over to the spare you have, so that when
the Win10 install is finished on the spare, the
spare can be erased.

All that the exercise does, is create the license
key on the Microsoft server, which will be used
at a later date. Since the serial numbers on the
computer won't change, if Win10 is ever installed
again, now it will have a key waiting for it,
to complete activation.

When you have "Win10 over Win7" booted, you can
try out the menus and so on. Before you wave goodbye
to it, shut down Win10 (from the power button thing
in the menus), take out the spare drive, and put
the original drive (with Win7) back in the machine.
So that nothing is changed.

While installing Windows 10 (using setup.exe off
the DVD since there is no ISO mounter in Win7), only
the spare drive should be present and plugged in.
This is to ensure nothing can harm the original
drive while this install happens.

You want to do the procedure on both machines,
so there is a 8500-specific key for the 8500
and a 780-specific key for the 780.

And based on the day I've had today, I'm getting
less and less interested in foisting Win10 on you :-)
I had a lot of trouble today, backing up Win10
with Macrium. I had to update my 6.3 version of
Macrium to 6.3.1685 so that a backup of Win10 1903
would complete. Until I did that, I was getting
"Error 9".

And even after upgrading the OS version from 1809
to 1903, the EventViewer still wouldn't work properly.
But in small print, I saw which file it was complaining
about, a view_1.xml file, that when I deleted it,
the EventViewer custom view started working again.

Just about everything I do, I'm fixin stuff...

Paul