Hi! Long time lurker. I cant really remember why :-S I think its your fic, or SPN episode reactions. Probably the fic.

Anyway, this happened to me and it ended up being a problem with windows media, something to do with one of my plug-ins. I think it might have been DIVX? But I remember when looking up how to fix it ALOT of people said it was a problem with their registry. Anyway if you just type into Google "streaming no sound" (without the speech marks) it'll come up with alot of solutions.

Hope this helps!