If your cpu has an igp plug your monitor into the mobo and test.
Get another monitor for a test.
One or the other test should help narrow it down.
When I first start my computer, either cold or awakened from Sleep, I get this "fuzz" that covers the whole screen, just for half a second, intermittently, and then it eventually normalizes.
This also happened once where the "fuzz" stayed on and I had to force a shutdown and restart. I had some audio on at the time, so I know it's not the hard drive, but I want to know if the problem is a symptom from the graphics card or the monitor. It's a GeForce GT 640 graphics card on an HP Pavilion 1320t desktop, running the latest Windows 10.

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