Do you mean no Audio Chipset? - If so you need to download those seperatly.
Let me guess this was a computer from Tiny Computers? And I bet the motherboard is a Micro-Star International.
What you might find useful is an app called Belarc, which runs on your PC and generates a report, which us techie's can use to help you out.
You can download it here:
http://www.download.com/Belarc-Advis...-10007277.html
Once that is complete, send me the report, and I will try and find the appropriate sound drivers.