You either have an incorrect driver, a bad fan (there is most likely more than one), or a clog in the cooling channel at some point, or a combination of all. Also, today's laptops MUST be used on a flat surface...not on carpet or a bed, and even if it is on your lap, you have to be sure that your leg doesn't block the fan on the bottom if there is one. Even the rubber feet on the bottom of a laptop are critical these days because on a flat surface, the feet raise the laptop enough for airflow. If the feet are missing, the laptop drops down and the airflow is dramatically reduced. It's true that changing the OS doesn't have a DIRECT effect, but unless the manufacturer of the laptop provides exact drivers for the OS you loaded, you may be running a driver that pushes your hardware, especially video, harder than it is designed to run. If you let Windows 7 pick it's own drivers, you are most likely in this boat. I recommend you reload the laptop back to it's factory OS and settings using the recovery disks and THEN see if the problem is still there. I'm betting it won't be.