How do you turn the mute off when it doesn't allow you to in system preferences> sound?

Question

the only thing i can select in the sound preferences is to show show volume in menu bar. And i cant hear music from itunes or anything else on my computer.

Answer 1

At the bottom right of the screen, there should be a picture of a speaker in the tray, click on the speaker ONCE then click the mute/unmute button and change the volume.