Sound has strangely quit working in Opensuse 11

Sound has stopped working. I don’t know what information I should even provide to get help. What do I do?

I recommend you start by trying to work your way through the audio troubleshooting guide (stop once your sound starts to work):
SDB:AudioTroubleshooting - openSUSE

If that doesn’t work for you, then please post here, and one of the more knowledgeable users (wrt to sound) on our forum will provide some specific suggestions.

If you are using an updated version of KDE4 try downgrading your phonon-backend-gstreamer to 4.2.11