You need the audio drivers for your device,
http://www.driversguide.com
user: drivers
pass: all
Search by the manufacturer or sound device name, download the drivers and install them. After you format usually there is a diskette with the sound device drivers, the device is there but has no recognition on your PC. All you need is the drivers and you'll be good to go.
It would help to know what sound device you have, there are millions of drivers out there.
Goodluck