You obviously do not have the sound drivers installed. If you have all installation CDs, reinstall sound drivers, if not DL from web.
This page contains the list of ASUS Motherboard drivers available for free download. This list is updated weekly, so you can always download a new driver or update.
Free asus sonicmaster driver download download software at UpdateStar - ASUS SonicMaster is a software solution that minimizes distortions in order to enhance sound.
Free Download Link: http:// Home page: http:// This Motherboard Drivers Download Utility.
Download ASUS Motherboard driver for Windows 7, 8, XP
Free Download Sound Driver Asus Motherboard P4v533
This page contains the list of ASUS Motherboard drivers available for free download. This list is updated weekly, so you can always download a new driver or update driver to the latest version here. We offer ASUS Motherboard drivers for Windows 8 32 bit / 64 bit, Windows 7 32 bit / 64 bit, Windows XP, Mac OS and Linux. It is very easy to download ASUS Motherboard driver.