Your monitor is showing some signs of deterioration. You changed it but when you installed the new monitor, it says, “Input Not Supported”.
To avoid this kind of problem, make sure to lower the resolution of your display by going to “Setting -> System -> Display”. Change to resolution that supports by all monitor which is 1024 x 768.
If changing the resolution does not fix the problem you may need to change the “refresh rate” of your display adapter by going to “Setting -> System -> Display -> Advanced display settings -> Display adaptor properties for Display 1 -> Monitor”.