Display resolution problemw with Dell Inspiron.... The only resolution that will fill the LCD

Question

The only resolution that will fill the LCD screen is the highest one. When I select a lower resolution instead of filling the LCD screen is just displays a smaller viewing area with a black border around it, it does not fill the entire screen. If I hook up an exterman monitor I can adjust the resolutions and each one does fill the external screen completely. I have tried a new video card (nVidia) and it does not fix the problem. I have tried downloading the latest driver for the video card and that does not work. It did not used to do this and just started lately. Is the problem with the inverter board behind the LCD screen?