Acer 2920 Audio Driver not detect

Hello,
My laptop Acer 2920 having this audio problem from 2 years around.
Once i format to XP from first day i bought it, im unable to detect my audio driver, but detect my Bluetooth driver as default sound driver.

In Volume Control properties show
Default device : Bluetooth Hands-free Audio

When i install Realtek Audio it's successful install.

Devise Manager :
PCI Device - unknown

How to solve this problem?