So today I installed an NVIDIA Quadro FX5600 in my 2008 Mac Pro (3.2GHz 8-Core, 2GB Ram etc. etc.), and when I plugged in my display (23" Apple Cinema) to the DVI-Out #1, I got a blank black screen. However, when I plugged it into the second DVI-Out port, it comes up with my desktop background and mouse curser, but no dock or menu.

I'm assuming the second DVI-Out is using my display as a second monitor, but really that's no good.

Does anyone have any helpful suggestions?