The only thing I could think of would be if the overscan/underscan settings are messing with the TV. over/underscan is not something that happens with VGA or even DVI, but tends to be used on HDMI since some TV's overscan the image and this setting lets you correct this.
Strange thing is that over/underscan should not actually alter the resolution and just scale the image to allow you to either remove black bars around it of shrink the image for it to all fit on screen.
1440 x 900(it is in fact a 16:10 resolution, something i have NEVER seen on a TV they all tend to be 16:9) is a very strange resolution for a tv to be honest. I wonder if it actually wants 720p(1366 x 768 for most tvs) or 1080p(1920 x 1080. long shot and scaling would make it look BAD) to scale with its built in scaling engine.
As long as you have your main screen on, you can play with resolution settings and always recover
Worst case, on a 19inch screen, I do not thing VGA will actually look that bad at all. It just will not be able to play bluray