Are you running Windows 10?

The restore settings are a little different for each windows, but the sound is pretty much the same.

Click on the windows button in the lower left and type 'system sounds' into the text box. Then open system sounds, go to the playback tab, and double click on the speakers. Then you can go to the levels tab and change the output sound level. You can also go to 'enhancements' and fiddle with things in there. Sometimes they prove to do the thing you're looking to do.