My LCD lately has been doing something really weird. Whenever I use a resolution smaller than the native one (800x600, 1024x768 etc), the LCD monitor doesn't stretch the screen to fit the the full screen. Instead it would be like an 800x600 window in the middle of a black 1280x1024 background. Any ideas on what might be the problem?
I have a ViewSonic CA902 LCD Monitor
I have just updated my Nvidia drivers but that didn't do crap. Although while I updated them, when I uninstalled the driver, it changed to 800x600 with a full screen.

The problem has been happening for a week or two but before that, the screen would have fit perfectly.
Sometimes the screen fits correctly when changed, for no apparent reason.

Oh and I'm using Windows 7