Mac sound?

[Rani]

Hi,

My Mac has just started to not work in regards to the sound. Whenever I try to adjust the volume with the keyboard, I get the attached picture.
I then went to system preferences and went to manually adjust it, but there were no selectable items in the output or input sections. No sound is coming out of my Mac. Can you help?
I don't know if there is something that I did wrong, or if this happens alot, because this Mac is about 7 months old.

Thanks,
R

 

[generdude]

Do you have anything plugged into your input jack on the back of your Mac?