GTX 560Ti HAWK and 2 displays??

so when i try to use 2 1080p monitors, both of them use DVI. i plugged in 1 monitor, it worked! and when u plugged in my 2nd monitor.... both monitors get no signal.... why is this? is the gtx 560ti not able to run 2 DVI monitors? also my 2nd monitor only has a HDMI and VGA port so im using a HDMI to DVI cable and a DVI-D to DVI-D on my main benq monitor.