I purchased an Intel NUC (NUC5CPYH), and installed the RAM and SSD, booted up fine, was able to install the OS, but upon reboot, it would never display anything on the screen, not even the POST screen (no signal at all from the NUC, monitor says no signal). I tried 3 different monitors using VGA and HDMI connections, and one TV. I tested the RAM in another PC using Memtest86+ and the built in Dell tool and it checked out okay. I then tested the SSD in desktop and it worked fine.
I tried to update the BIOS using the recovery method (with the jumper), and it never seemed to take. So, I did an RMA with Intel, and the replacement NUC did the EXACT same thing. This time around, I figured out that if I swapped the RAM to another stick of a different size, it would boot one time, and one time only. I had to swap back to the original stick to get it boot and then it would boot one time. It's like somehow the warning that shows the system RAM size changing did something that allowed it to start.
So swapping out sticks I eventually was able to update to the latest BIOS (v43) using the recovery method (with the jumper). Now, I can get it to come up and show POST and get into the BIOS every time using the same stick of RAM. However, the problem I have at the moment is now it won't boot an OS from anything, not even the SSD. Signal does get to the monitor, but it's just a black screen after the POST is finished. I've tried multiple bootable USB flash drives (including System Rescue CD, a Grub4Dos one I made myself, and the Debian 8.0 installer). I tried using the flash drives in every port of the NUC, front and back. All of these bootable flash drives boot fine when used with another PC. I tried loading the optimized defaults, and turning on fast boot. The flash drives show up when I do the one time boot selection (F10) and I'm able to pick them. I tried booting using both legacy and UEFI options.
Before I RMA this unit, I was wondering if there is anything else I can possibly try? I've looked around on the Internet and many people had the same no display issue, but for most, if it was resolved, it was done by updating the BIOS. No cases I could find ever resulted in not being able to boot an OS after that.