Hi Saltgrass
I believe that historically, when I updated from Win 7 to 10, The resulting OS was BIOS (not UEFI).
When my system crashed 5 days ago, I successfully recovered it from a USB RAM drive but into UEFI mode.
My Widows Backup on an external hard drive (the one that's the only way I have to get back to my original configuration)
was made prior to the recent crash and so is BIOS mode.
All of this was done on the same desktop PC.
Now, I've tried the MBR2GPT utility with no success.
I then did a clean installation which was successful,
I've checked the boot mode and it's definitely UEFI.
What I couldn't see or didn't find was any option to do this clean installation in BIOS mode instead of UEFI.
I'm guessing that if I could do this, then my Legacy/MBR System Image would be accepted.