Well, I am going to answer my own problem I found by fault finding. It turned out to be the HDMI cable. When I purchased two of them for my original dual monitors, I ordered the top of the range able to do 4K, etc, obviously they were not. In my ignorance, I didn't even know at the time that their were different types. So for any young players out there or even old players, if you are going to purchase a Hi Res monitor, make sure you have the right HDMI cable. The one that comes with the monitor was not long enough for my set up.