Help needed-dual monitor/2nd video card not recognized - Dell

I'm trying to run a dual-monitor system. I'm looking for help as to why I can't get my system to recognize the second monitor and the onboard video card now that I've installed an add-in video card.

SYSTEM AND SOFTWARE DETAILS
1. Two monitors on a Dell Dimension 4700 Form Factor.
2. First video card is factory installed card (onboard built in).
3. Second video card (low profile) PCI Express GeForce 6500.
4. Running XP, patched sp2, Bios A04.
5. Checked setup, but no options to change my video preferences.
6. Display properties, settings tab does not show second monitor capabilities.
7. Only one monitor works when it is plugged into the second video card, not the onboard video card.

WHAT I'VE DONE SO FAR
1. I installed second video card (low profile) PCI Express GeForce 6500 into the PCI bus.
2. I plugged my monitor into the new card video port.
3. Started the PC search for drivers. MS could not find any.
4. I ran the installation CD from GForce.
5. Restarted computer.
6. So now I get what looks like a DOS screen and an error message that says "unsupported video configuration detected" and "system halted!".
7. Then the screen message directs me to plug the monitor into the add-in graphics card and restart.
8. DMAN systems tab shows only one video card present, not two. It shows the new card, not my onboard.

THE QUESTION
8. Is there any way I can make this work? What am I missing?

Thanks, anyone, for any tips you can give me.

Alright, you guys....Just to avoid any of you doing any heavy lifting I am posting my own solution to my own post. Apparently, Dell's form factor Dimension 4700c's error message stating "UNSUPORTED CONFIGURATION" means just that. Nobody anywhere knows how to activate the onboard video card when a second add-in video card has been installed. Luckly, the video card I purchased had a DVI port, as well as my second monitor. I simply purchased a VDI cable and plugged 'er in. Voila. Now I have two functioning monitors running from my Dimension 4700c form factor computer. I am also lucky I did not wait for any of you guys to wade in and offer timely solutions for this, I am better off you did'nt.