I have MacBook Pro 13" Early 2011. Model A1278. When is try to change the volume the icon is greyed out. When I reboot, there is no chime. And when I go into the sound settings, it doesn't show an output or input. I have tried resetting the PRAM and the SMC. I have tried a clean install, didn't help. I have tried plugging in headphones, there is no red light in the port. I went into safe boot, the sound does not work in there either. Also, there is no song through the headphone either. PLEASE don't suggest I go to apple, I don't have apple care and am comfortable opening up my mac. Any help will be appreciated.