Dual Monitor Support?

[The Admiral]

I have a Compaq Evo D510 with factory-installed everything. I have a need for two monitors, so I bought a standard nVidia GeForce (6?) PCI card and installed it. Both monitors work properly alone, but there seems to be no way to set it up for dual-monitor use (in the BIOS or Display Properties.) The computer is running Win XP Pro SP1.

How can I get it to work?

-Steven
Harman Music Group