Hey guys! So I have a MBP 15" Late 2011 and I've installed 6GB (yeah, I know) of RAM. So, I will admit, this thing has taken a couple of hits. Nothing direct though thanks to my messenger back. Anyway, I was in quite a rush in NYC, and I was running from Penn Station up to Port Authority on a Saturday night (dumb idea). So, this guy decides not to move when he sees me coming, and instead goes out of his way to knock me into a light post. Okay, so the laptop hit the light post. No performance damage, nothing done. My messenger bag saved it. That's fine. I check it out on the train to make sure nothing was wrong. Everything's fine. So I get back home, open it up, use it, no problem. Then I close the screen. I hear this sound, which sounds *exactly* like a knuckle popping. Like the soft pop though, nothing harsh. It's more of an annoyance than anything else. As far as whether or not it's the sudden-motion sensor, I can guarantee you 100% that it's not. That sounds more like a zip. It's related to my screen, so you can rule that out. I'm not sure if anyone else has this problem and/or would know how to fix it. I've tried opening up the back to see if anything seemed out of place, but I didn't mess around too long. It was more of just a quick look, then I closed it. Halp?