Can I install another video card on my Win7 desktop with ATI All-in-Wonder HD?

I have 2 PCI slots and a PCI Express x1 available and I'd love to have a third monitor. Can I install a second video card without problems? I currently have an ATI All-in-Wonder HD card in the PCI Express x16 slot. Any recommendations? Feedback?|||that will depend on your motherboard, if your motherboard supports ATI's crossfire technology, and both of your graphics card support it, it should work no problem, provided you have a strong enough PSU as well of course..