Not sure about this one but try going into safe mode and sign in on the administrator account and try it again.
Or try this sourced from another forum:
The Windows Audio service is dependent on other services, which are running. So, go to Start and type services.msc in the Search box. Then press CTRL+SHIFT+ENTER to run as a Administrator. Once it opens, go to Windows Audio service and double-click on it. It will open Windows Audio Properties page. Click on Dependencies. It will show something like Multimedia Class Scheduler, Remote Procedure Call (RPC) and Windows Audio Endpoint Builder. These are the Services. Ensure that all these services are running by checking in the list.