No sound on 2009 macbook

This mac runs Snow leopard, in the Sound Properties, the Output Volume bar is shaded out so the slider cannot move and the speaker icon on the desktop is also shaded out, the MUTE box is not checked, any ideas please?

Take a close look inside the headphone jack; is there a red light showing? Even if it's not showing, the jack could be stuck in output mode. Try using a sturdy toothpick and wiggle it around inside of the jack in order to release it from output mode. By the way, this is a common problem.

The headphone jack seems to be out of line, like it dropped down a little so the speaker 1/8 plug does not fit into the headphone out but why would this prevent sound from an mp3 or youtube video?

If the jack is defective or stuck in output mode, the symptom you described in your first post is what you would see. It would not be limited to MP3s or YouTube videos.

ok, got it, will it a try and let you know, thanks!