u can use an onboard graphics card only with a PCI video card, but you cannot have two agp cards in, once u install the second card, right click on desktop and go properties, go to settings and if both monitors are setup and both video cards are setup, then in settings there should be 2 monitor screen pictures, click on the second choice monitor and click the "extend my desktop on this monitor", then u should be able to use the second screen to drag apps onto.