"Stop Code: KMode Exception Not Handled" issue

My HP laptop with Windows 10 hangs at bootup with the following notice:

"Stop Code: KMode Exception Not Handled." This notice is followed by "Preparing automatic repair" that hangs. I even waited overnight for HP to perform the "automatic repair."

STEPS I TRIED:
~ Ran diagnotics (F2). All h'ware passed testing.
~ Disconnected power, pressed power button for 30 seconds then tried to access Start Menu, tapping Esc key during bootup.
~ Forced shutdown twice (also 3 times).
~ Restored BIOS settings to default.
~ Set USB drive first in boot order and booted up with bootable Windows 10 boot tool on a USB flash drive.
~ During bootup, I tried tapping Esc, F9 and F10; but each effort leads to the "Preparing automatic repair," which hangs.

Is there anything else I can try?

 

Problem solved! Windows in the partition that normally permits a factory reset became corrupted. Installing a fresh cop of the OS worked. I guess the Stop Code means failed OS. Since the S/N was inaccessible, I had to buy Windows again. Sigh!