Imac's Sound and Mic stopped working!

Last night my Imac's sound stopped working. Internal speakers don't work, plugging in external speakers don't work. I thought this was just a hardware problem, but my internal mic also doesn't work, which is on the other side of the computer....

I've rebooted many times, cleared the pram, checked my preferences, played with the audio midi controls, plugged and unplugged the cord in the line out and did everything besides dance around the mac singing.

Any suggestions on how or why this would just stop working? It has to be something i'm missing, some setting.

I've downloaded Line In, didnt do anything. I downloaded Sunflower, didn't do anything.
The only thing I can think of is I just loaded Parallels and Win XP, but I just uninstalled it and still no solution.

Help please!!

What OS are u using on the iMac?

Collin Bl said:

What OS are u using on the iMac?

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Snow Leopard
10.6.3

I'm thinking it was because I plugged something into the audio line in, and maybe, even though its not plugged in still, it thinks something is?? Does that make sense? That explains the internal mic not working, but not the sound...

So as an added point, I can now play a stereo THROUGH the imac, meaning line in to line out speakers, but only when the mac is powered down...so its not a hardware problem...they work....settings somewhere??

Sometimes, launching GarageBand works, when I have sound issues. The problem usually clears up.

iWhat said:

Sometimes, launching GarageBand works, when I have sound issues. The problem usually clears up.

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Tried it. Still nothing. The keyboard makes no sounds. The preferences on Garageband let me pick two audio outs, but called the same name, but neither work.

So is there a way to access or see the internal system volume control? I've tried everything else, and can get sound when the computer is off through the line in and out, so I'm thinking its an internal volume that is off for some reason.
In terminal or singer user, is there a command to see what the system volume is, and to change it if is off??

Ok so I did a reinstall of Snow Leopard (light install, without formatting the HD), and sound still doesn't work. Should I do a full refresh install, formatting the HD?? Like i said before, sound works when computer is off and the stereo is plugged into line-in and speakers are plugged in....