I have had this freezing issue for a while now when coming back from sleep or shut down. I've noticed It hardly happens in the summer but almost every day in the winter. It definitely has to do with the temperature outside. I usually let it sleep most of the time and after a period of inactivity of let's say 2 hours min (again, I suspect hardware needs a bit of time to get below a certain temperature), it will run fine for 30sec-2min and then it freezes. Fixable only with a hard reset. I suspected for a long time that might be the sleep mode, but it does the same thing if it's coming from shut down too. When powered on, it will run roughly for the same amount of time (30 sec-2 min) and freezes - sometime with the system still loading which I found it strange. This is definitely a hardware issue, some say it's this hot to cold when powered off or put to sleep that upsets the graphics side. Anybody with a solution to this?