What source should I consult to find out why my computer does not function with my new LCD monitor?

I have a Quicksilver G4 mac (using OSX 10.3.9) that has a Nvidia GeForce2 MX graphics card. I recently purchased a Samsung 204B LCD monitor It has both VGA and DVI inputs and offers the ability to rotate the screen from landscape to portrait mode. I can use the DVI input and the rotate feature on my new macbook (intel 950 graphics card) (using OS X 10.4.3) but not on the older G4. Only the VGA input works.Is this a graphics card issue? Can it be tweaked? Who should I ask? How can I tell if another card will support the features?

check the users manual. It should have been shipped with the monitor. Should have the supports in there.

Try lowering your screen resolution to 640X480 (256 Color) That should activate it to default detection mode.It Usually happens when the Video card is set to a Non-Standard Refresh rate. Or Set to a resolution the LCD can't handle.

the monitor website, probabley needs drivers