This is for Realtek AC'97. On the Realtek page, download the driver under the Windows 98Gold/98se/Me/2000/XP/2003 and to the right it says A3.75 ( not the beta version ). I dont think site 1 works but it looks like sites 2 and 3 do.
Below is the Realtek page to download the CODECs driver V A3.75 from the Realtek site.