Just FYI, when I say run Ubuntu from a disk, I mean from a DVD - so I wasn't trying to install Ubuntu anywhere on the computer.

core i7, 16 GB, 120GB SSD, 2TB HD, radeon graphic, MSI mobo Win 10 up from 8.1.

Rather perplexing boot problem. I use my computer fine, turn it off. Next day I can't boot. You get the screen that...