Most computers should be OK with this and just treat the card as another video adapter. Ideally you would disable the onboard video, but this is not a requirement under most circumstances. I have PCs at work that needed a dual monitor setup and we just added a single PCI card and used it in conjunction with the onboard video to output to two monitors. However, most modern video cards already have (at least) two video outs... unless you need MORE monitors than that, just disable the onboard. Hey, think of it this way... that stops it from using up RAM.