How to fix my Macbook sound problem!?

I own a MacBook and not a long time ago, my sound just stopped working. For no reason, i think. It only works when I plug headphones or other speakers in, but without them, the laptop can't find it's own speakers. :S
Also there is a red light shining where you put in the headphones.
When I try to change the sound there is a 'forbidden' symbol under the volume.
In the system preferences, sound, output it says:
"Digital Out- Type: Built-in Output"
"The selected device has no output controls"
This is really strange...
Does anyone know how to fix this problem?

i would contact apple…… but call them!!! i have a macbook to and i called apple they said ship it to us and we’ll give you a brand new one. but my warranty was good so that’s why they said we’ll give you a new one. and it worked. so try calling.