I got a Benq led BL2201pt that i used to connect to my pc with a dvi connected, and that have always worked. But since i have gotten a third screen i had to hook this Benq screen to my pc with a dp -> mdp cable, the strange this is that the 2 other screens that i have connected works just fine if the Benq screen is not connected. But when i connect the Benq, the 2 other screens black out and my Benq starts telling "No Cable Connected"
Just in case, then my graphic card is a ati hd 7950, and my 2 other monitors are hooked up with dvi and hdmi.
If anyone can help it would me much appreciated.