aoc LM 729 lcd monitor problem

The monitor will come on display the windows logo wait for the desktop to come up then a few seconds later a black screen. If I power off and back on the screen comes back on only for a few seconds. It does this even if I pull the video cable out and back in. When I right click on the desktop change resolution the screen comes back on displays auto config and shuts back off again. The whole time the computer is on the power light is green when I turn the computer off the no signal prompt comes up and the power light turns orange.