bad motherboard symptoms. my hp pavilion does what yours is doing. it will boot up rarely now. it comes on fans and all and it gets hot quick and turns off or restarts. if you have a warranty id def. use it. heat issues causing it to shut off like that are motherboard/cpu related. hell your cpu fan can work and it still shut off like mine does. in some cases the cpu fan quits working and yeah the cpu gets hot and shuts the computer off so it wont damage it.