We can see that the volume icon is X in the lower right corner. Based on the small series experience, it should be caused by the service being not started.
One is that "audio service is not running" but the computer has sound, and the other is that when "audio service is not running", the computer has no sound. First, make sure that the sound and the connection are normal.
1. Click "Start Menu" on the computer to search for the service. Then, click "windows audio", as shown in the following figure;
2. After the selection, right-click "windows audio" and click "properties" in the pop-up menu. Then, click "log on" and set "logon option" to "local system account", then, click "application", set "logon option" to "specified account" again, and select "local service" account at the bottom --- click "OK" to exit, restart the computer;
3. If you are using another version of windows 7, after "audio service is not running" appears, right-click the "windows audio" service and select "restart ", now the problem is solved.