I'm running Ubuntu 14.04 on an Intel NUC and it won't boot! The last successful boot was earlier today but now each time I try it gets stuck on the Grub menu where it prompts for memory check etc. This is not a dual boot system, so this screen shouldn't ever appear, and it never has before.

It's GRUB version 2.02~beta2-9, which is a little disconcerting, as I'm on the stable sources.

Unfortunately the keyboard (I've tried 2 keyboards just in case) is not responding at this point in the boot process, so I can't select the "Ubuntu" menu option in Grub. The keyboard works during the bios stage, so I can configure it to boot from USB, and I tried a flash drive with 14.04 on it. The flash drive works in my laptop but is completely ignored by the NUC (I tried all 3 USB ports!).

It seems that I have no way of getting into the machine at all! The Intel support site was my first option, but the site is down. I expect it's a long shot, but if anyone has any ideas I'd be very grateful.