I get nothing but a blank screen when I power on my DN2820FYKH. Memory is 2G ADATA AD73I1B0887EV. (I've also tried a Hynix HMT325S6CFR8C that worked fine before I moved it from my laptop to the NUC).
Display is a Dell 1980x1280 monitor, HDMI cable plugged into the monitor and into the NUC. If I plug the NUC side of the cable into my laptop, the monitor works fine.
When I press the power button, the button light turns white and I can hear the hard drive spinning, so it was power. Nothing happens on the screen though.
I've tried holding down F2 or F10 during power-up. Nothing happens.
The memory you're using appears to be 1.5v memory. The DN2820, like all current generation NUCs, only supports 1.35v memory.