This is my first post, and I apologize as it's a little long. I just wanted to get the whole story on the table and clarified. I've had one of the new Aluminum 13" MacBooks (2.0GHz C2D) since Christmas Eve. A few weeks ago, it accidentally fell off my desk at work (not a far drop , but far enough for my heart to stop for a few minutes) when I got tripped up in the power cord under the desk. For all intents and purposes, the MacBok seemed to work fine. I had one of our IT staff, who happened to be a trained Apple repair tech, take a look at it; the only real damage was that the display hinge had been knocked a little out of alignment. Just ot be on the safe side, I took the machine to the Apple Store, where they told me not to worry about attempting to get the hinge fixed (because I'd be paying a lot of money for such minor work), and the Genius sold me a hardcover plastic Speck case for the MacBook. While the Speck case certainly looked nice and madethe already sturdy laptop feel sturdier and "protected", I was a little concerned about the amount of heat the machine was giving off within the case. On Sunday, I unplugged the machine from the MagSafe charger for a few hours and left it closed in sleep mode. When I woke it back up, the fan on the left continually gave off some sort of high-pitched whine whenever the computer was in idle mode. I Googled, searching this site and others, and read about the "CPU whine" in the previous generation MacBooks and MacBook Pros. I also saw where a few people with new Aluminum MacBooks were having this same issue or something similar: http://forums.macrumors.com/showthread.php?t=639660 http://forums.macrumors.com/showthread.php?t=649950&highlight=whine+macbook http://forums.macrumors.com/showthread.php?t=458379&highlight=whine+macbook http://forums.macrumors.com/showthread.php?t=656279&highlight=whine+macbook It seems to only make the noise when the computer is running off of the battery - plugging in the MagSafe charger makes the noise quiet 85% of the time (I've found that plugging, unplugging, and replugging will not stop the whine from occurring). I tried installing QuietMBP as was recommended in some posts, but the only setting that will stop the computer from whining is the "highest" setting (that is, allowing the processor 0 seconds of idle time), which causes QuietMBP to eat up 30% of my processor usage in Activity Monitor and to start the fans going (and, presumably, to significantly lower my battery life). I don't know whether all of this was the result of the MacBook falling, from it overheating in the case, or something that "just happened". I set up an appointment with the Genius bar for today at 4 PM, but Idiscovered another odd occurance when I set up a new account for the Apple Store (rather than give them my password) The noise never happened under the new account. Never. I left the machine idle until any and all initial processes were done. No noise. I checked Activity Monitor for stray processes. None. And no noise. Now I'm bewildered. Could something have gone wrong somewhere in my account, leading to a corruption of a power management utility or process? I'm not canceling my appointment, but I am going to try a few things before I leave. I've already repaired disk permissions, and I'm about ot reinstall the 10.5.6 OS X combo update. Should I try to reset the PRAM too? What other options should I be looking at? Or should I just wait, and let the Genius Bar folks look into it? As a note, I'm aware I may have to pay for any repairs because they may or may not blame them on the MacBook having dropped (despite two to three weeks passing between the fall and this issue arising), and I'm okay with paying for reapirs (though I will try my best to argue my case, of course).