There is a bug in the Windows bootloader that I have yet to find a workaround for. Here it is and how to trigger it.

HIBERNATE the laptop.
Chnage RAM size.
The laptop may fail to boot and show a blinking cursor in the top left corner.

Sorry, I only know how to create the issue. I learned about it the hard way and to get out I changed the ram back to the same size then booted up but next time did not hibernate but SHUT DOWN.

I have not tested out the theory that booting off an UBUNTU CD may let us delete the hiberfil.sys file to correct the issue. You do that test.