I've read about this problem before and HERE IS THE PROBLEM (I can almost GUARANTEE IT!)
You got an Audigy 2 ZS OEM, perhaps from ebay? Anyway the thing is it is an OEM for some computer brand (Dell, HP, what have you) and creative did something VERY stupid with it - specialized it slightly for the OEM computer maker! Model number is the same yes, but for example, if you notice the model number is THE EXACT SAME on an audigy 2 as the ZS. So if you google the serial number (I think it is, or one of those numbers on there other than model at the top edge of the card) you may come up with a link to Dell, HP, Gateway, etc. Download those drivers from there and those will work!
Don't ask why creative did that but it is VERY stupid. I didn't realize this until after I bought my card off ebay, fortunately it was a standard retail card.
Before anyone gets any funny ideas, the OEM cards from newegg are NOT AFFECTED because they are plain old audigy 2 ZS cards. Only the OEM cards from an OEM builder like Dell, HP, etc. have that problem.
Hope that clears up the problems you are having. Google it. There is a way to make the drivers from creative work (hack somehow) but not exactly sure. Google it