i bet twilight is 100% right. your temps are probably too high and the laptop shuts down to keep from killing it self. check temps. u mostlikely have a loose heatsink or a mad fan. could even just be some dust clogging up the fan. it most definitely is gonna be heat. if for some reason it isnt, your motherboard is trash, you probably have some power issues on the board and u might as well scrap it.