I have a unibody Macbook pro that's out of warranty + I don't have Apple Care. Yesterday it stopped going to sleep upon being closed. It just continues to run until the battery dies (it doesn't even hibernate for some reason, I have to set up the clock and re-enter my wifi keychain password everytime I let it drain). I option+command+eject it to sleep, it still works fine, the issue is only when closing the lid. I generally fix issues myself whenever I come across them. Here, I'm guessing the magnetic sensor is malfunctioning (I did not magnetize it).. any idea on how one goes about remedying this?