So, I turned on Internet sharing over AirPort and Bluetooth PAN, and at first, the WiFi icon in the toolbar showed the vertical arrow symbol and everything worked fine. Now, it all of a sudden started turning off randomly. It completely refuses to turn on now. Even though it shows Internet sharing is ON, the AirPort card remains OFF and refuses to budge no matter how many times I click "Turn On". Any ideas on why it's doing this??