Ensure your motherboard or sound card uses an AC'97 chipset (like the ALC650, ALC655, or ALC850).
Check the BIOS/UEFI settings to ensure the "Onboard Audio" is enabled and set to "AC97" mode rather than "Auto" or "HD Audio."
This driver is for the AC'97 codec only. It will not work for modern "Realtek High Definition Audio" (ALC series) hardware. Installation Instructions
Windows 98, Windows Me, Windows 2000, Windows XP (32/64-bit), and Windows Server 2003. Limited Support: Windows Vista and Windows 7 (32/64-bit).