Laptop Automatically turn off in Random time

My Laptop automatically shutdown when i am starting a day then computer on atleast 10 minutes but after when i plug usb cable and acess internet through via usb tethering then system 5 min on after it shutdown. after that i am again press power button and turn on it is start but at the boot process shutdown it take same when i start pc. my laptop fan working but fan small damage and processor paste refill. the problem start with when i install a game it overheating my pc so my pc goes turn off. but uninstall game and start it same over heating problem so i am open laptop and remove some dust in fan and paste to processor but not effect. Please solve my problem. also one thing when i am start my laptop start with another position which ia shown in attachment file then start to small time. also attached a video file that show how my laptop goes turn off in zip file.