When I first got my laptop, I set it to hibernate after 2 hours of non-use. Like all good computers, it did what it was told. For a couple months. It soon stayed on all night without going into hibernation, or even standby. It's gone into hibernation mode by itself twice since February, and in the past few days, it's gone into hibernation mode when it's supposed to every time it's supposed to. Did it randomly fix itself, or what? Is there a logical explanation?