1. Download this software from this link : http://www.filehippo.com/download_cpuz/download/4763ba97972f241bde7599dc9b91a5eb/
2. Install that software.
3. Run that software and go to the mainboard tab.
4. Under the mainboard tab you'll find the name of your motherboard.
5. Search your motherboard on GOOGLE, it will take you to the site of your motherboard.
6. There you'll find option to download sound drivers for your PC.
download audio drivers for Windows XP