my computer has stopped making any noise (playing sound clips or web video clips) if use a web browser either IE or firefox and the wbpage got some music attached to it, or maybe youtube nothing will come out my speakers!

if the webpage opens windows media player all is fine and i can hear again

i have no quick launch icon no more for speaker control! but i can get it up through control panel, but still no sound in web pages

any ideas please guys?