There are 2 most used Microsoft Universal Architechture Bus (MS-UAA) Driver which is Article Base 888111 (KB888111) and Article Base 835221 (KB835221). This patch/drivers normally required before installing audio drivers. Certain vendor such as Realtek already package their drivers with required MS-UAA.
Base on current laptop situation, the audio drivers which need MS-UAA is IDT and Conexant audio drivers. This patch normally apply only in windows XP, and prior OS.
For downloads and information you can refer here: