What operating system are you running? WinXP should find the drivers itself. Otherwise you can go to add/remove hardware in the control panel and try to install the device drivers from there. Put in your Windows CD-ROM and tell the program to look on the CD. Then it should find the drivers on the disc and install them for you.
If this doesn't work then try this:
You need to install the device drivers manually. You can get them from
www.driverguide.com. Open the device mananger and look to see what the name of the hardware is. If it doesn't say then, look up your motherboard on the net. You may have to get some serial or model numbers that are on the baord in order to find the right chipset that came with the board. Once you find the sound or audio device names then you can download the drivers from the website I gave you. Really there is no other way of finding out what the names for your sound/audio devices are other than that. After you download and install the device drivers for your sound devices then Restart your computer. Then you should have sound.
Hope this helps! Get back to me if you need more assistance.