Ive tried everything, and the audio on my macbook still wont work!

I have looked through forums for a couple days now and still cannot find the answer to why my audio will not work on my macbook (7,1 , running on snow leopard 10.6.3)
Symptoms:
*No volume control icon on top right of screen
*When the volume buttons are pushed (f11, f12), the 'speaker' part of the audio pop up is grayed out, and there is a small circle with a line through under the volume level measurement meter
*There is NO red light coming from the headphone jack, and i dont use the headphones often
*In System Preferences>Sound, no audio input/output can be found
*Sound does work for the Startup Chime, but nowhere else
*Apple hardware test did not help
*Applications>Utilities>Audio MIDI Setup, could not find any input/output for the audio
I am stuck and nothing is working. Help?

Which MacBook is it? Why haven't you upgraded to 10.6.8? Try Onyx

I think it is the newest one it says its a macbook7,1 if that helps. I just recently erased the old hard drive and did a new clean install with snow leopard 10.6.3

As BlueRoom suggested . . . . .DL 10.6.8 Combo Update install. Repair Permssions via Disk Utility on yourHD Log out then back in and report back.

Oh and welcome to the forums.

Cheers

thanks guys, it was as simple as upgrading my operating system. i dont know how/why it worked but it did!