I was fiddling around with the settings of my audio. And after changing a setting, all output except system sounds stopped working. The specific setting is found when you click the loudspeaker icon on the lower right. Then click on the icon above the system-wide volume control. This opens a new window. Then in the third tab (can't tell the English name, I have a Dutch Windows) the first setting.
When I changed this, all sound output stopped working, except for system sounds. I've had this before, and a restart usually fixes this. But I want to know how to fix this without rebooting. It would also be handy if someone could tell me why this happens.