This sounds like video pixels aren't getting clocked into the monitor at the right pixel time or phase, so noise gets in and causes random colors. Or video card is toast.
so I would check in order of "its a pain to do"- -
that the DVI cable's well plugged in, its screwed in well, swap out...
I had the same no-video problem, when playing videos in Media player.
So I right-clicked on the desktop and went into:
/Display properties/settings/advanced/troubleshoot/hardware acceleration.
And pulled the control left a little below 100%. This fixed the video so it works.
I guess my...