Acer extensa 5420 won't turn on

Hello,
So I'm a little behind on the times and have never had a lap top or decent computer. Someone
Recently just have me this laptop. theres nothing wrong with it except it occasionally doesnt
Want to come on. She said she has to hold it with her hand gripped on the back of it and press the button. Theres nothing wrong with the battery. Sometimes it comes on just fine. Right now when I turn it on how it usually works, the power light comes on, the farthest left light of the three next to the power button comes on, turns off, comes on again, then all the lights shut off. Nothing ever comes on the screen. It makes a slight.regular noise while it's attempting to turn on.