there no active mixer devices available....

有时候停止了系统的window audio服务时，点击任务栏右边的音量图标时会出现：

there no active mixer devices available. To install mixer device,to go control panel,click printer and other hardwares ,and click add hardwares."

前提条件是在声卡驱动正常的情况下：　　

解决方法：

  只需要开户系统服务（Windows Audio ）即可，服务描述：

"Manages audio devices for Windows-based programs. If this service is stopped, audio devices and effects will not function properly. If this service is disabled, any services that explicitly depend on it will fail to start." 

只要保证该服务运行即可。