Zkus, VB nepoužívám...

While VM is stopped:

Go to Settings in the machine drop down menu and click Audio
Changed Audio controller to ICH AC97
After running Windows XP in Virtual Box

Right-click My Computer and click Manage
Click Device Manager, right-click Audio Hardware and click Update driver
The Found new Hardware window opens. Click on Not this time > Choose Manually > Choose from list.
Select Audio etc., then select Intel 82801AA AC’97 Controller