yes; xorg.conf in 10.04 is no longer the standard... you can generate one.. it will use it when it's there.
here's how to do that;
login with your username and password.
Switch to a tty ( press ctrl+alt+f1 (f2,f3 etc)
stop gdm with
then generate a xorg.conf with
sudo service gdm stop
this will create a xorg.conf.new in your home directory)
sudo Xorg -configure
move the auto-generated xorg.conf.new to /etc/X11/xorg.conf
Make changes you want to try
sudo mv xorg.conf.new /etc/X11/xorg.conf
and start gdm again with
sudo nano /etc/X11/xorg.conf
sudo service gdm start