A display that was stressed by a brown out or surge as part of the power outage could be damaged and you where fortunate to get 5 extra days out of it vs being dead on the day of the problem. Looks like a new display is needed. If you have an extra display available to test with you could isolate it better to the display itself as the problem. If computer has HDMI output to connect to a TV or you have a TV with VGA input and it has a VGA output you could try connecting computer to the TV and see that the display shows fine on the TV etc, then know for certain that the monitor is the problem and not video cable or video card etc. Its most likely a dead display.