log out and restart xserver fc6?

[Tom Poe]

I have two computers.  One monitor.  The settings on one computer with 
old monitor seemed OK.  When I hooked up new monitor, it now reads in 
Administration -> Display:
resolution: 1400x1050
millions colors

The other computer (my newer one) keeps defaulting to:
640x480
thousands colors

I checked the older computer's xorg.conf file and it reads:
Section "Screen"
     Identifier     "Screen0"
     Device     "Videocard0"
     DefaultDepth     24
     Subsection "Display"
          Viewport     0  0
          Depth     24
     EndSubSection
EndSection

When I try to set the newer computer to the same settings, it invariably 
defaults to the 640x480 settings, or goes whacky, and can't load 
xserver.  I then have to go to terminal and run:
#  system-config-display --reconfig --set-resolution 1024x768 
--set-depth 16 and restart computer to get back to 640x480 settings.  
Confusing to say the least.

Is there another file involved that I don't know about?  Is there a 
special order to go about changing resolution and depth?
Tom