Okay so I just had itunes and firefox open. And out of the blue I hear this loud sound. At first I thought it was just the natural hard drive noises- but no, I realize this thing is freaking loud. I pause itunes and I lay my head to the left of the trackpad. My mbp is making a very loud hum-ish/buzz-ish somethng sound. I can't describe it really. Not normal. Never heard before. I immediately close firefox and itunes. When I reopen itunes, it won't let me hide by using commands. It freezes and I'm forced to force quit it. The sound starts to gradually fade into the normal hard drive sounds. What just happened?