Trouble with a D620 and Docking station

I have recently come across a wierd issue. I have a D620 laptop that plugs into a docking station that has a keyboard, mouse, internet, and LCD monitor connected to it. When the display appears on the LCD it has black on the top and bottem of the screen than a thin piece where you can see the desktop, almost like a dvd movie format. I’ve tried disconnecting all connections, resizing, checking the drivers but not luck. Any help would be greatly appreciated.