One day my monitors stopped displaying picture. I tried every possible plug, then took out my graphics card and used the onboard video. Picture was displaying. Ok, so then I tried two other graphics cards. No picture each time. I switched out a generic power supply at 470w for a evga at 500w. Still no picture. The one gpu I wanted to work was an old radeon hd 6790, which was my second attempt at installing a graphics card. The first that stopped displaying picture was a generic card. Any idea how to fix this, or is something wrong with the motherboard to allow anything but onboard?