Sorry, monitor turns blue/black more like, maybe a tad of gray. We've done nothing new or different to anything. Another new thing too is the desktop icons keep moving after I put them somewhere. Just like two of them. I did change or refresh the monitor yesterday but nothing changed. Now it keeps vasculating/flickering like it can't make it's mind up what it wants to do! I did do this mr. fix it thing and it found three sleep issues and stayed asleep with no color change, then two hours later, back to the same thing.
That lighter screen with no image is from the monitor detecting a signal but no image. Say if it's cycling though the connections or if the video card is saying it's connected and working but not sending a full video signal. Try resetting the monitor settings to default, install the latest BIOS, chipset, power management and video drivers for your system, and see if it does the same thing.
You can also set the power management settings in the monitor itself to turn off after so long without a signal if you have not done that.