Make sure that your onboard sound is disabled first. If it's in BIOS it should be under 'Integrated Peripherals". If it's a jumper, check the manual---well, check that anyway. ;)
I'm not 100% sure, but I believe Creative only has updates to their drivers for download, but I could be wrong. The way it was when I had an Audigy was that you needed to install the drivers off the CD and if you wanted updates, you downloaded them from the Creative site.