Macbook pro os x sound stopped working

MacBook Pro Sound Stopped Suddenly

Volume Control at Icon Bar says full throttle on.
System Preferences have no mutes selected and all ranges set to maximum sound.
Restarted Computer.
Nothing new downloaded. No recent upgrades installed. It just stopped working.
The speakers sound when the machine restarts so I know they work.

No Sound from mp3s, videos, or websites. It is as if my laptop suddenly became mute.

If you can help with a solution, i would be most appreciative. Thank you.

******************

I subsequently installed ten updates. The problem still exists as described above.

SOLUTION!!!

I have used PCs forever. I recently, just about three months ago, converted to MAC. I have always been hesitant due to the many glitches and crashes which are reported rampantly by those whom I know in the recording and graphic design fields - though they swear by their MACs. It has never made much sense to me. Now I am hooked. I love my MAC and am thrilled with what I have been able to do on it in just three months.

Now I face the above problem with no solution in sight anywhere on any of the resource sites available on the net. Hours and hours and hours of research and emails and registrations and consultations with no solution. So here I sit frustrated beyond measure because I JUST FIXED THE PROBLEM.

This is going to sound incredibly stupid and moronic but I swear it is true. I started to play with the volume at the top icon bar - raising it and lowering it repeatedly just out of frustration. And voila. The sound magically returned after about ten cycles. It came back just as mysteriously as it disappeared.

Woohoo! At least there is a solution on this one.

I'm glad to hear that your sound came back and thanks for letting us know. I am a bit concerned why it was not working properly in the first place. If you run into any more difficulties with it in the future, I recommend a trip to your local Apple store and have them run diagnostics.