So a few days ago my laptop started making this beautiful noise. It comes from the speakers and nothing can stop it. Sometimes it stops on its own but if I do anything that makes a sound (play a video, increase/decrease volume, ect...) the noise comes back again. Yesterday I ran the extensive apple hardware test and when I restarted the problem went away. But today the problem returned. If I plug in headphones or speakers into the audio out the sound stops coming from the macbook pro speakers and starts coming out of the attached device. Opening and closing photobooth does nothing. Getting the CPU up to 100% does nothing. Screen brightness does not effect the intensity. It makes the noise running on battery power or if it is plugged in. It also makes the noise if nothing is attached to the laptop. If I press down on the left side near where the speaker is it changes the pitch and sometimes makes it quieter. I bought this on July 07, 2008 so it was the newest model at that time.