For what its worth, I had the exact same problem, only in XP. Creative hasn't released drivers that will work on every machine. I downloaded drivers from Creative, driverguide, and every other resource on the net. And never did find anything that would work. The drivers built in to XP will make the soundcard function, but with none of the features that make that card so cool. In researching the matter, I found a whole slew of people with the exact problem in XP. I can only assume that the problem carried over to Vista. I can't tell you why the drivers work on some machines but not on others. I've got 5 different SB Live cards here, all different versions, and the problem remains the same. If you cant find a solution to the problem, use the workaround. Uninstall all the audio software that you loaded from Creative, shut down, remove sound card, boot back up to make sure it's not gonna be looking for drivers. Shut down, put the soundcard back in (different slot if you've got a spare), boot back up and see if you can get it to load the drivers from the OS. Go into device manager and see if the card is listed as being installed. That's what I had to do with XP. That, and some free software from the net gave me the functionality I needed.
Good Luck,
MediaGuy1974