right, i'm sorry for reopening a dead thread, and i've just registered to say this.
i've found a solution that works for me

i'm running vista homebasic on a ms-7046 exactly the same as yours. i've been trying to find a solution for this audio problem for hours, and i've found one that works for me.
first off
download these drivers from MSI:
http://www.msi.com/index.php?func=dr...e&dno=2418&i=0
then extract and run the setup for windows xp service pack 2 (right click setup.exe, click properties, then under compatibilty, choose run for 'windows xp service pack 2'). then click apply and run the setup as admin.
reboot and you should have working audio
Rob