can't play to LCD projector

[Jason Pinkney]

Dear List,
I'm having trouble using my laptop with an LCD projector
(for presentations) ever since I installed FC2.  The current
WinXP OS works in this regard.  My old RH7.3 OS also used to
work smoothly.  However, that was a custom built
kernel from the manufacturer of my laptop, and the FC2 kernel is
standard (not customized).

I know how to obtain many different resolutions
and HFL/VFL's on the laptop screen using xrandr and the F7
key.  I know that F8 should toggle the signal to the external monitor.
I expected 640x480, 70 Hz Vsync, and 16 bit resolution to work, but the best
I can get is the top left corner of my display appearing on the projector
(with bad colors).

I have tried many different options and settings in my Xorg.conf
file, so I hesitate in sending one. 
So let me first ask: 
is there any reason to expect the FC2/Xorg system to fail where the RH7.3
system succeeded?

thanks for any wisdom,
Jason