Insert the driver CD that came with your computer and install sound drivers from this. Typically it would be a setup.exe file, which you double-click on and let it install the drivers.
You can read basic guidelines of how to install drivers : http://www.ehow.com/how_4999826_install-so...windows-pc.html
If you do not have driver cd, you can download from youe motherboard manufacturer's website OR your computer manufacturer's web site. Look in the Support section > Downloads. You need to enter your computer / motherboard model for this.
You can find out about your motherboard model etc using SIW : http://www.gtopala.com/siw-download.html
Edited by Romeo29, 20 May 2009 - 11:14 AM.