the file you are after is in etc/X11/ to get there, open konqueror, then, pres the up arrow a few times until you see it. another way to edit the file:

1 ) open a console
2 ) type in su and press enter
3 ) type in root's password, you won't see anything as you type the password,it's a security feature, and press enter
4 )type in kate etc/X11/xorg.conf and press enter.

the file should now open, ready for editing

andy