Hello Mlatou, I’m sorry to hear that you are having problems with this your NUC when trying to use dual display.
It is very important to keep in mind that this specific NUC support Windows 7, Windows 8 and Windows 8.1 64-bit only.
There are some customers reporting compatibility with Linux flavor OS, however Intel has not validated them. The following link has some for additional support on Linux Intel® NUC Boards and Kits — Linux* support
Our graphics drivers are based on Windows Operating system. This is the latest driver for a 64bit OS Download Center , and for 32 bit Download Center
Check the steps listed in the Multiple Display FAQ at Graphics — Multiple Displays frequently asked questions.
Check the troubleshooting steps listed on the HDMI FAQ at Graphics — HDMI Technology FAQ.
In addition to that, I found a thread about some customers using a VGA adapter. You may want to check it out. MiniDP to VGA Adapter That Works with D54250WYK
Regards