I have a laptop that I have had since June and I don't remembering it doing this when I first got it. what it is doing is I will boot up my laptop, use it and then close the lid and putting it to sleep. I have sometimes forgotten to shut it down when I go to bed but when I return the next morning is is shut down. I have it running off the power cord not battery. Is there a setting I can change or what is going on? Does it automatically shut down after a lenght of tim in sleep?