strange sound crash

The sound just crashed while i was watching youtube.
I tested another outlet and it worked, but strangely the player didnt play from youtube, but the same player (and others) played music from harddisc.

Suddenly the pc just froze and I couldnt ctrl-alt-del. I turned it off manually and it worked, although the boot was much longer than usual.

It has worked on three reboots now and the broken sound outled works again.

I didnt get any errors messages so this just confuses me.

Anybody know what may have happened and what I should do?