I recently lost all sound both on my computer and my wives computer. Having posted the problem on help sites, I received assistance but noithing worked, I decided to go back into Device Manager and the sound icon, opened it up, right clicked and just read the info. It said that if after updating the drivers you experienced problems try rolling back to the previous update. This I did and now instead of the sound driver just saying 'high definition sound' it now read 'Realtek high definition sound' and the sound was back. On checking my wives computer, it was the same so I 'rolled back' the driver with the same result. Whats puzzling, is what caused the problem in the first place to both computers, which ARE NOT networked? Maybe our experience may be of help to someone?