The past six months my MacBook hasn't been shutting down. Let me explain. It acts like it shuts down; it logs me out, the screen goes black, and by all appearances it's turned off. But there's a quiet high-pitched whine if I put my ear next to the keyboard. If I press the power button to turn it on (I "shut it down" remember) nothing happens. If I hold the power button down for 10 seconds the whine goes away. I then try turning it on and everything starts great except for that on startup it tells me OS X quit unexpectedly and would I like to send an error report. I've tried logging out manually and then shutting down from the login screen but it does the same thing. Any ideas? PS- It only does this in OS X and not Windows, leading me to believe that it's a software problem and not hardware.