Only "turn off appear" after switched on

Hello,
I got kinda problem here.
Last month I bought new notebook and my sis borowed it. I didn't know what she did with that notebook. but, when she returned the notebook to me, I switched only "TURN OFF COMPUTER" appear. I have no choice but to click the "TURN OFF COMPUTER". I try to boot or choose safe mode but same words came out. I didn't know what happened and I have no idea on what should I do to resolve this problem. So, I would like to ask for an opinion on how should I do when this kind of problem. Thank you!