multimedia audio controller

You need to provide more information such as the make and model of your computer. The first place to look is the manufacturer's (Dell, Lenovo, Asus, HP, etc.) site and look under support for Downloads/Drivers. If it is a custom built computer and the audio is built in then you need to check the motherboard site for the driver. If it is a sound card you installed then you need to check the sound card maker's site.