the ram is accessible from the bottom of the laptop. there is usually a screwed on cover that will give access to it. there should be a number of these but the one for the ram will have a symbol of a ram stick to let you know this is what is under it. other ones should be the hdd cover and possibly others.
i am leaning toward the power supply having gone bad. if none of these obvious solutions, and it is perfectly possible a good jarring of the laptop popped the ram loose, then the next check will be with a new power supply. you can get them at walmart, best buy and plenty of other places. generic ones can work on many different brands, but there should be hp specific ones as well that cover a number of models each. if it works, then keep it, it it does not, then return it.
i make this suggestion assuming the laptop does nothing but blink when you try to turn it on. does it also do this with only the battery installed and it not plugged in? if it does absolutely nothing with the battery but blinks with it plugged in, this tells me the battery is dead and did not recharge and the power supply is not doing it's job. if it also blinks with the battery and unplugged this is more along what you are thinking which is the laptop is dead.