I have a new macbook and I am having trouble with the sound after I unplug my headphones. Once I unplug my headphones, my sound will not come out of my regular macbook speakers. When I push the volume up, down, or mute, it shows a circle with a line through it like saying "no sound" and the headphones hole is a red light. When I go to "Sound" under System Preferences, under digital output it says the selected device has no output controls. Does anyone know how to help me?