screen not turning on

my brother gave me a broken Alienware M15 r3 laptop main part of the laptop seems fine but it has no screen but i can plug it into a monitor by hdmi cable i got it to work for some time i was able to do gaming and etc. but now when i go to turn it on it seems to be runing but no signal was being sent to the monitor so i tried to change the display settings in vr by connecting to my pc with virtual desktop and it connects but still a black screen presents itself still