A few things that can cause this type of issue are either security features on the system or if the monitor is too bright.
First, make sure that any virus protection is off as well as the Windows built in security which are Windows Defender UAC, User Account Control. The following links will walk you through shutting these settings off on your computer. After shutting off UAC your computer will force you to reboot so you may want to shut that one off last.
Shutting off UAC:
Shutting off Windows Defender:
Also, if the monitor has DDC built into it that should be shut off within the OSD of the monitors menu. All monitors can be different but most have this option within the "Other" settings.