The_Contractor - 12:59 am on Aug 15, 2005 (gmt 0)

I would install new drivers which should take care of the conflicting devices (maybe). Go to device manager after driver installation/reboot. Delete everything under "monitors" and then shut-down. Disconnect the 15-inch and hook up the new display and then start up normally.
If it doesn't work and it is indeed incompatible you can pickup a GeForce 6800 based video card for well under $200 and an Radeon X800 based card for around that also which are compatible with that display. I am running a Quadro FX700 based card in my workstation, but I would prefer an ATI based card (personal preference).

It's the wide-screen aspect ratio of the display that makes it incompatible with all but the latest cards.