New Win7 install, triple monitors, 1 monitor displays lots of grains

I don't know what it is, but it's not the monitor or the graphics card that is faulty.
The monitor doesn't just display these grains, it updates them. Most of them are flashing constantly.
The GPU is fine because the 2nd monitor is also put on that card and is displaying correctly.
And I'm certain since the monitor displays correctly in win10
I think it's a driver issue but installing latest GPU drivers didn't solve this issue.

See post #3 for pictures

You might be better off posting the screenshots here at Sevenforums, rather than using Dropbox. Many members won't click to offsite pictures and websites because of malware concerns. It's easy to do, and here is a tutorial on how to do it:

Screenshots and Files - Upload and Post in Seven Forums

What connection is being used on this monitor? HDMI, DVI or VGA?

It really looks like the symptoms of signal reflection in a VGA cable...

Are all 3 monitors the same resolution? Can you swap cables to see if the problem stays with a specific cable or a specific graphics port?