Post Screen is GREEN on HP Z2 Mini G5 Workstation

[nebosite]

I am re-installing windows on my new HP Z2 Mini G5 Workstation, and for some reason when it boots up now, the initial POST screen with the big Z on it is green (instead of black) and the font text is cyan (instead of white).   

Once windows fully boots up off the M2 drive, the monitor colors are normal, but during the windows install the color weirdness remains, making it very difficult to read the text (see photo).

I have rebooted the machine a few times and unplugged the monitor cable, but the green screen remains.   The fact that the POST screen is green suggests this is a hardware problem.   Ideas of what is wrong?   Anything I should try?  

See:   Should be a black background and normal looking windows dialog here:

Update:   I updated to the latest bios and did a cmos reset and this did not improve the situation.   In fact it is worse now because after install Win 10 enterprise, the computer is always in the green mode, so I think I might have a bad board.

Here is what the post screen looks like:

[BeemerBiker]

Try a different DP  / HDMI cable and a different connector depending on your configuration or options.  Look for debris in connectors..  

Are you using DP to DVI-D ?  If so, check that one of the DVI-D pins is not pushed back in the socket or connector to where it is not touching.  If HDMI adapter look for debris there.

You mentioned that the colors are good after windows starts.  That is suspicious.

Try running one of the windows color tests to make sure all the colors are good.

The Microsoft store has "Monitor Colour Test" which shows 6 colors plus black and white.