Laptop Problems

When it turns on it is fine adn runs then just shuts off all of a sudden. Nothing is loose or no noises at all,it just happened when i had it on my lap the other day adn i tilted it sideways a lil bit and it happened. I think it might just be like u stated,something loose or a chip on the board going bad,but who knows…i am NO computer guy when it comes to that stuff.