All you need for a monitor is to tell the computer its vertical and horizontal sync, look up your monitor and try find this, might also be on the back, then edit /etc/X11/xorg/xorg.conf and look in the monitor section and make sure the values match.
If that dosnt fix it the problem would be your GPU i rekon
hope that helps somewhat :/
Cheers to the community for all the awsome work :)
Main PC Os: FC15, Win7 CPU: Intel i7-2600K Ram: 2x4 gig DDR3 1600C7 Video card: Nvidia EVGA GTX570-OC
HP Proliant N36L Microserver Os: FC14 Ram: 2x4 gig DDR3 1333C8 TV Tuner: WinTV HVR-2200