If you are using 2 memory sticks please use only one and try again.
There is only one slot for RAM.
Please remove the Msata and the network card and try to access the BIOS pressing the F2 key.
I have no idea how it is possible to remove a network card, because it is integrated into the NUC. I tried to launch the board without ethernet connection and without sata. Pressing F2 while booting doesn't help. I see the same picture: the monitor is black.
Would you please check if the BIOS jumper is the correct position? Position 1 and 2
I checked. It was in the first position. I tried to change the position, nothing changed.