You went here I take it, and got the correct driver...
http://www.sis.com/download/download_step1.php
Did you run the file after you unzipped it?
This is what it says in the readme file
SiS 7012 PCI Audio Driver Setup Readme File
-------------------------------------------
To install Windows 95/98/Me/NT4/Win2000/WinXP drivers, please run SETUP.EXE in this directory;
To uninstall Windows 95/98/Me/NT4/Win2000/WinXP drivers, please run Control_Panel-> Add/Remove_Program->SiS Audio Driver
To install drivers for other O.S, please see README file under each
driver directory.
SETUP.EXE Automatically installs WDM or VxD driver for Windows 95/98 base on
the O.S version:
-WDM driver is installed for Windows 98SE and
-VxD is installed for Windows 98OEM (first edition, 4.10.1998) and
Windows 95.
To force installing VxD driver for Windows 98SE, please run
"SETUP.EXE -vxd" using Windows Start->Run
To update the driver, just run SETUP.EXE directly. SETUP will overwrite
the old driver with the current one.