No audio output detected!

Hi,
I'm experiencing a weird problem since 3 days.
There is no audio at all in my mac pro. In the system preferences it says no audio output detected.
I searched the web so i :
- Reset the VRAM (commande option p r )
- I repaired permissions.
- I installed the lastest updates for my mac.
- I made sur it's not an earphone problem (the red light of death), because there is no sound at all with or without the earphones.

Now i know also that it's not a hardwar probem, because when i start my mac with the cmd+option+p+r it makes the starting sound!!!!

Please help me, i bought this 2009's mac 3 days ago and i can't even listen to music
Thank you

PS : i have Mac OSX Lion

 

I have mac osx Lion and in the system -> audio : audio identifier: 0

 

This is a clean install of Lion, i had leopard on it before and audio didn't work in leopard neither.
Is it possible that it could be a hardwar problem even if i have the starting sound when a start my mac?

 

tried it, but it doesn't work, it says no audio device found. God...

 

Ok thank you for all your replies.
So for people who have the same problem as me and don't find a solution (and don't want to pay to repaire ) i solved my problem by installing AirPhones application on my iphone and Mac, so that the sound is streamed via wifi to my iphone.
This way i don't have a completly mute mac. But it can be only temporary, because it works only when your connected to wifi and you know the sound in the iphone is poor.