I need help with my asus laptop!

Hello, So i have a asus laptop and when i turned it on the screen went black but it was suppose to be the page that i type my password in but it just went black i turned it off and back on i could choose from start windows normally or it said startup repair (recommened ) i clicked it, it worked. But the next day it had the same problem i clicked startup repair(recomened) it did'nt work i kept trying and trying but the screen was still black. What do I do?????? Help!