I was using my 9315 in tablet mode. I noticed the battery was low. So I put it into sleep mode and plugged it in. I came back a couple of hours later to find that out was very hot all over. Screen was hot, sides were hot, and entire back was very hot. I managed to wake it up and shut it down as well as unplugging it. It took it a few minutes to cool off enough to actually hold it as a tablet. Is this normal or was there a runaway process? How can I tell what caused this overheating?