I just performed a clean install of Windows Vista Home premium on my system.
Unfortunately, Vista won't recognize my sound card (a SoundBlaster Audigy 2)
and it doesn't appear in the system devices list. As part of the preinstall,
I downloaded the Vista compatible drivers, but when I tried to install them,
I get a message saying my sound card doesn't exist. The card worked fine
with XP.

HELP!!!!

I gave up on Creative Sound cards because I experienced this problem
frequently with Audigy cards on a variety of XP systems (different Intel and
AMD platforms, a variety of BIOSes). I have two of them sitting in my
drawer.
The best I could ever do was to get the cards to work with basic drivers but
not the Creative software required for full functionality.
Take out the card, reboot, shut down.
Make sure in the BIOS that the motherboard sound system is turned off.
Reinsert the card.
If the card is not recognized have the OS search for new hardware. If the
card is recognized you have to point the installer to the basic drivers.
If you can get the card to work under these circumstances you will not
likely get most or any of the Creative software to work with it. In fact
when I could get the Audigy cards to work at all Creative's own software
would say there was no sound card installed on the system.
Creative "support" was less than useless.
In truth, except for those who use their computer for professional audio,
even if you can get the Creative cards to work there is little advantage to
them over on motherboard audio for the vast majority of users. Most computer
speakers and headphones, regardless of price, are incapable of high fidelity
sound anyway.