You will need to tell us more information. What are you using, onboard sound or a discrete sound card?
If you are using a discrete sound card, then find the make and model and search it up on the manufacturer's website.
If you are using onboard, then you'll need to know the motherboard model and then find the driver on the website.
If you don't know the motherboard make and model, search up the make and model of the computer you bought (if it is from a computer manufacturer like HP or ACER) else, you'll need to open up your computer and tell us the motherboard.
If you tell us one of the three either
1. make and model of your sound card
2. motherboard make and model
3. The computer make and model
we can hopefully help you find the driver