Picture doesnt fill screen - Cinema HD - early 2007

Ok so I have an early 2007 Mac Pro G5 Desktop. 4 gb memory Running OS X OS X 10.8.3 (12D78) 2x 2.8 Ghz Quad Core Intel Xeon

When I go to into system preferences and click "Displays" two windows come up. Cinema HD (the monitor I use) and VGA. My computer doesn't have a VGA port. Nor do I have a second monitor. On top of that I can not have the picture fill the screen. I try switches the resolution in the ciema display panel and nothing happens. When I go to the VGA panel (System Preferences>Displays) and change the resolution it works...but it still doesn't fill my Cinema HD 30" screen. I have black bars on both sides of the picture. so Im not getting the wide resolution.

I do have multiple video cards...four to be exact. Is this a sign that the card is damaged? When I switch video card ports it'll go back to normal however, once I restart or power down, it goes back to where I can't change the view to fit the screen.