Computer turning on but screen is black

I've had this Lenovo Ideapad P400 for a while, probably two-three years and it's really nice! I've been away from my laptop for about a month and a half. Now, I go to turn it on and the keyboard lights work but the screen is just black. I've tried to Shift + F8 and then Power but nothing. I'm NOT A COMPUTER TECH, so i don't know terms and stuff this is all very confusing.