My HP laptop Compaq nx9030 - keeps shutting down for no reason. Now it won't even fire up at all. I had a new motherboard about a month ago courtesy of HP. Since then it's had this problem. It did it earlier in the week but then then next day it worked ok for a few days. I just wondered is there some sort of thermal cutout to prevent overheating? There is a 40Gb HD and about 2.5Gb free space.