I have an ASUS G550 laptop, and recently it has started to shut down after a few minutes with the lid closed. I have it connected to an external monitor so i dont want that to happen. I have set all the power options to do nothing when I close the lid, and to never shut down the hard drive and all that stuff, and I do not think it is overheating because it doesnt shut down when the laptop monitor is lit and it does not get warm.