As was previously stated, the Realtech website. Or you can go to the Intell
website, look up your mother board and download from there. Or, If you have
your original driver disk, use it. Then just go to Windows update, choose
the custom option, look under Hardware Updates and you shuld see the latest
version listed and install it from there.
I've installed SP3 Many, many times and never seen the audio drivers broken
from the install on an Intel based system. It's broken Windows update about
half the time, but that's a pretty easy fix.
Keith