No Sound in Lion

[supanatral]

For some reason I can't get any sound on my macbook pro which is running Lion.

When I try turn up the sound, it's crossed out (see attached)

[Satcomer]

Open System Preferences->Sound, Output tab. See if you muted your sound system.

[DeltaMac]

If that doesn't help - have you tried a PRAM reset?

[supanatral]

If that doesn't help - have you tried a PRAM reset?

I have reset the PRAM however it's still not working.

Open System Preferences->Sound, Output tab. See if you muted your sound system.

I have attached a screenshot of what I see.

[DeltaMac]

Correct!
If you have a digital output (toslink cable) connected, then you can't adjust the output volume. You would adjust the volume on your output device.

If you don't ever use an optical audio out, then look inside the output port on your MacBook Pro. Do you see the red light inside?
That will usually reset (unstick) by inserting your headphones, or whatever you use, then remove. Do that a coupe of times. If you do have a toslink cable, then that's ideal to try the hardware reset on that port. If you can get the red light to go out, then you should be back to normal.

[supanatral]

Thanks, DeltaMac!

You taught me two things:
1. How to fix my issue
2. Theres a light in that port. I NEVER knew that

[DeltaMac]

The light is the LED used for the optical audio. It's powered on when the optical port is activated, which is actually behind the normal analog port (using the same opening)
Both the input, and output ports have that dual port. Sometimes that switch gets stuck. It's a fairly common question in these threads.