For simplest understanding. Go to Control Panel > Device Manager > Sound, Video and Game Controllers > (right click on the specific audio devices, click properties, go to the Driver tab, and then click Update Driver).
(Driver Update Windows 7 - How to Update Drivers in Windows 7 - Device Driver Update)
You should use the device manager to keep all your drivers up-to-date, as sometimes Window's doesn't catch all your driver updates.
(Keep in mind, Viri get in, when you don't have things fully updated, so it's good to keep them up-to-date! )
If you have any questions, just let me know.