Ideas:

Go look at the system. Is it a factory made computer, or a build-your-own PC?

- Factory made, get the make and model, go look it up (also known as STFW).

- BYOPC, this is a little tougher. You'll actually have to do some WORK. Open the case. Observe the sound card. Make a not of anything identifying (like BRAND or MODEL). STFW.

That should help you locate the appropriate drivers.