I've been having this strange issue rather recently. Before the beginning of this week, my PC was able to hand 2 monitors and occasionally a large TV whenever I wanted to watch a film in bed. One monitor is connected via VGA, the other via DVI, with the TV via HDMI, all through the NVIDIA GeForce 770. They all worked with 1920x1080 display and the TV was usually duplicated from one of my monitors. Recently however I've had the issue where, even though my PC has registered the TV, the TV's display is black, I thought maybe this was the cable, but I have tried one spare and one new cable since and both yielded the same result. I have also attempted to fix this by using the motherboards own display, however, the problem here is that it refuses to up the resolution above 1024x768, meaning I can't duplicate my display when I try and set it above that said resolution, the screen once again goes black. I have no idea what is causing this as nothing has changed, I even re-downloaded old drivers for the GeForce 770 to see if that may have been the problem but apparently not.