How to determine Xorg configuration file in use?

[Victor Marquez]

Hi all,

I am trying to add resolution options to the graphical environment but 
can not find the appropriate configuration file in use.

I added my resolution option to /etc/X11/xorg.conf and to 
/etc/XF86Config and did tellinit 3 and tellinit 5 each time. After that 
I do not see the new option added to the list when I access System 
Settings... Display... Settings.

This is how I added the option:

Section "Screen"
         Identifier "Screen0"
         Device     "Videocard0"
         Monitor    "Monitor0"
         DefaultDepth     24
         SubSection "Display"
                 Viewport   0 0
                 Depth     16
                 Modes    "1280x800" "1024x768" "800x600" "640x480"
         EndSubSection
         SubSection "Display"
                 Viewport   0 0
                 Depth     24
                 Modes    "1280x800" "1024x768" "800x600" "640x480"
         EndSubSection
EndSection

I am using FC3 as VMware guest OS under Windows XP.

I have a laptop with monitor at 1280x800.

I have read man xorg.conf and tried to determine the appropriate file by 
looking at the paths this man page says xorg searches and still can not 
find the appropriate file.

I can not find the -config option because I do not know where xorg is 
started. Looked at /etc/inittab and it runs /etc/X11/prefdm -nodaemon 
but I believe it is not started there. Or it is?

My environment seems not to have a $XORGCONFIG variable set (echo 
$XORGCONFIG returns a blank line).

Can somebody help me please?

Thanks a lot in advance.

Victor Marquez