Start X with error message "No Devices Detected"

Just changed the video card on my testing PC and it boots up with the following error message:

(EE) No devices detected.
Fatal server error:
no screens found

I seldom use X so it takes me some time to troubleshoot. Finally I got the solution from X Wiki:

http://wiki.x.org

You can go to /etc/sysconfig/hwconf, and search for "VIDEO" to see what video card you are using. Then check if it matches with your X configuration file /etc/X11/xorg.conf.

If seems you are using the correct driver but still get this message, it is likely that your chipset isn't support on your Linux distro yet. You can try the vesa driver or the vga driver. In my case, the vesa driver solved my problem.

Section "Device"
Identifier "Videocard0"
Driver "vesa"
EndSection