Hello Chris

Welcome to PCHF
The first thing to note is that when you install a video card into an PCI-E, AGP, or PCI slot, the on-board graphics will stop working. So to run duel monitors, you won't be able to hook one monitor up into the on-board port and one into the video card port.
If you want to run duel monitors, you can do it one of two ways. You can add yet another video card into one of the available PCI slots (not PCI-E) and hook one monitor up to each video card, or you can replace your ATI card with a card that has duel monitor support. Basically it will have two video ports.
Hope that helps!
