Windows 10: Why does the border of my monitor turn dark after some time?

When I start my computer, the monitor is clear and bright. However, after using my desktop for about an hour, the boundary of the monitor turns dark and blank. I have set it at the recommended resolution of 3840 x 2160.

:)

 

border on monitor

thank you, I appreciate your help. However, as I mentioned inmy initial email, "I have 2 monitors that are working. the Left monitor has a 2 inch border on the right side. the resolution is 1440x900. If
use the recommended 1600x 900resolution the windows icon disappears from the right side of the screen.

the "recommended" setting is worse.

any other suggestions?

 

My monitor keeps going dark for about a second

My monitor has been turning going dark for a second or two and it happens multiple times a day, sometimes I'll happen multiple times with only a few minutes in between, and some times it'll be hours in between. It never lasts for much longer than a second
or two, and it doesn't happen from being bumped or anything. Any suggestions would be appreciated.

 

Getting Dark Black Border on Laptop Screen.

Hi Microsoft Team,

I am today getting Dark Black Border on My Windows 10 Laptop Sceen. I did Trouble Shooting steps as well like Search - CMD (Run as Administrator) "sfc /scannow" & completed the process & shown message noting found. Still this did not resolve the issue. Still
black Border is shown.

Request to please help me with the soultion for resolution of My issue as soon as possible.