Monitor cuts out when HDMI/DVI is plugged in.

[Remo97]

So. My monitor turns on . the red light is on and the LG logo is on. I turn on the PC and the Monitor cuts off, its light cuts out and the screen cuts out. I un plug it/ plug it back in and it will no longer turn on at all, after about an hour I then got it to turn on again, it was find unti I plugged its end of the HDMI into my GPU. Weird..... So I tried DVI. it does the same, as soon as it plugs into my GPU it just cuts off..