Hi Friend, In this case I would recommend you to please try and connect any external monitor to the system to check if the issue is with the video card or the monitor itself..
If the external one also has the same issue like this original monitor, then I would recommend you to please try and update the video drivers for the system..
If the display on the external one is fine, then it indicates that the issue is with the original monitor itself, so, you can try resetting the monitor settings to factory defaults or, the monitor needs to be checked by the vendor itself.
Please let me know if it was of some help?
Thank you.