Four days after installing Windows 10 everything seemed to be going well, then on Saturday my computer's speakers stopped working. I can hear through my headphones but I have no volume control. 

In the Events panel of the audio codec details I see : "Device installed 29-Jul-15 8:40:12 PM stwrt64.inf" which is about when the problem arose.

Can I restore my previous audio driver? If so, what are the steps?

Many thanks,

Mike L