How do I upgrade my video card?

I am runnign XP. I have a ATI All-In-Wonder 128 Pro PCI card with analog out. I also have an ATI All-In-Wonder 7500 AGP type with digital out. My monitor has a digital and analog cable and a switch to manually switch from A to D. If I install the 7500 and the 128 Pro together and connect the A cable to the 128 Pro and the D to the 7500 AGP it will boot up and just before the XP login screen, I can see a cursor in analog mode only and it never boots any further. Digital mode is a blank screen. If I boot with just the 7500 in, I get blank screen (in digital) and cannot tell if it is trying to install the new hardware or not because I'm doing it blind. How can boot my PC with the 7500 AGP card only (with the digital cable) and get the drivers installed so I can start using it. Thanks.|||no. something could be wrong with your video card. i would install one (AGP) by itself since its a faster bus speed or wait i forgot which one was faster damn lol. but either way if it were to install new driver your computer screen would still show. if you have another computer try that out if not you might want to take it to a tech to see if your video cards are still working. could be the mother board as well.|||if i were you, i'd just add a new one to your system already and go with dual monitors! much better!|||Most BIOS settings can be set to either AGP or PCI or Onboard. Make sure your BIOS settings are correct first thing.