High Definition Audio Driver(2K/XP/2K3) is a System Utilities software developed by Realtek Semiconductor Corp. After our trial and test, the software is proved to be official, secure and free. Here is the official description for High Definition Audio Driver(2K/XP/2K3):

Audio drivers available for download from the Realtek website are general drivers for our audio ICs, and may not offer the customizations made by your system/motherboard manufacturer. To be sure you obtain the full features/customizations provided in your original audio product, please download the latest drivers from your system/motherboard manufacturer's website.

This is the Realtek High Definition Audio Driver For Windows 2000,2003,XP.