I have to setup a couple of computers at work to run dual monitors. They are older computers (probably Pentium 4s) running XP and I believe they have onboard video. Do I just need to find any video card with 2 outputs that fits whatever kind of expansion slot is in the computer (I would guess they probably have PCI due to they are a few years old)? Or can you use the onboard video with one monitor and a video card with the other? I don't need anything fancy, they don't do anything graphics intensive.