I have a Mac Pro Dual-Core Intel Xeon 2.66 GHz and am looking to get a 3rd monitor up and running. I installed a 2nd video card, a NVIDIA GeForce 7300 GT to hook up the 3rd monitor. It's currently connected via a DVI to VGA adapter. The Mac says it recognizes that there is a 3rd monitor hooked up and the 3rd monitor turns on with the mac purple light burst and stars background image showing. But the mouse cursor won't move over onto the 3rd monitor nor can I drag any open windows over to it. Is there a fix for this or any troubleshooting I can do? Or do I need to use a Mini DisplayPort + USB to Dual-Link DVI Adapter as well? This seemed like as easy, simple task to do at first. Thought installing a 2nd video card would do the trick, so any advice would be helpful. Thanks.