Windows 10: 1/8th of my screen is black and I can't fullscreen any apps into it.

When I open any app, 1/8th of the screen is black and it won't let me fullscreen my app without pressing F11 which is different than pressing fullscreen for me. and when I look at my notifications, it shows it where there isn't black.

:)

 

Blank screen in fullscreen apps

I opened IE, watched a video in fullscreen on YouTube but after a few videos, a black screen appeared in fullscreen with a green square on it and when I switched app to a game, (in fullscreen) the screen went black but I heard sounds. When I pressed power
and vol-up buttons to take a screenshot, it blinked with the real image and saving screenshot text, but went black again. I could switch apps, but when the app was opened it went black.

What has happened? I have almost no memory remaining on my SD card or phone internal memory.

 

Black screen when opening / closing certain fullscreen apps

I recently got a new monitor, and whenever I open or tab out of certain fullscreen apps, the screen goes black for a few seconds.

It doesn't happen to every app in fullscreen. For example, when opening / closing minecraft, the screen does go black, but when I open a modded minecraft instance through an IDE, the screen doesn't go black when opening / closing minecraft.

The only way I've found to stop the black screen is setting my monitor to 60Hz, which I'm not going to do as one of the reasons I bought it is for its higher refresh rate.

 

Fullscreen (Black Screen

Could it be registry? Because all it is is that I can't go in fullscreen on anything without black screen