Usually you want need to set the
xorg.conf file yourself since settings are automatically determined.
Most options can be guessed from the Xorg log at
0 is the display number). If you've an i5 or i7 processor, you're likely using the
intel driver (the log will have a line with "(II) intel: Driver for Intel Integrated Graphics Chipsets: ...").
If you still want to proceed generating the
/etc/X11/xorg.conf file, you need to run
Xorg -configure as root without an active X server. Disabling the X server will make you loose your graphical session, so make sure that you've saved all work and logged out. When ready, switch to a virtual console by pressing Ctrl + Alt + F1 and login the text console. First, stop the desktop manager:
sudo stop gdm or if you're not using GNOME but KDE:
sudo stop kdm. After that, you can run
sudo Xorg -configure. After that, you can run
sudo start gdm or
sudo start kdm to get back to the graphical session. If not, (re)move the generated