laptop slammed shut! Help

Help!!
Hi this is the usual title I guess.

I have a problem with my laptop,My son ‘fell’ on it yesterday and ever since it won’t start. It will display the usual and when it has finished with the little green lines moving across the screen under ‘Windows’ it just goes blank.

I have tried trouble shooting from the start up menu, checking for problems etc and after it has run through it just stops.

The computer was open at the time of accident, as he fell he says it slammed shut.

Any ideas?