Are you using OSX86Tools to try and create a device (EFI) string to add to your com.apple.Boot.plist?
Is there a way to change the resolution of my 9800GT 1G. I tried using Ox86Tools and it caused another problem...I get the blue screen after boot, when I press the power button it looks like the system is turning off. I press it again and OSX opens up with the new resolution. Every time I start the system I have to do this. What should I have done? I've done a lot of reading, but once again I don't understand what I'm looking at. Can it be fixed, or do I have to reinstall (again).
What happened when you first installed your system using my guide and added the com.apple.Boot.plist from my Support Files? I ask because that has the GraphicsEnabler boot option which should work for your card. You shouldn't have to re-install your retail Snow Leopard system as you wouldn't have touched it.
What happens to your video when you boot from the BootCD?