Dual Monitors, cant strech desktop :-(

Hi, I have a computer with Windows XP. The computer has 2 video cards, I have a monitor plugged into each video card. When I turn on the computer I see the exact same thing in both monitors. Since I want the image stretched into both monitors as one huge desktop, I go to settings in display properties but windows only sees one monitor there. If I go to device manager, I only see ONE video card (Intel 82945G) and if I go to the utility that came with the driver of that video card it also does not see the second monitor. My goal is to stretch the desktop into both monitors, as I sad before as of now I see the same thing on both monitors. Your help will be greatly appreciated. Also I noticed that when I open the computer case, one of the video cards is integrated with the motherboard but the second video cars is just a cable with the 15 pin video connection at one end and at the other end there is a 10 or so pins that go straight into some pins in the motherboard...weird, so is not PCI. AGP or PCIe....just a cable with a video connection at one end and at the other end some pins that go into straight into the motherboard. The second video card doe snot have a board or anything like that.