Hey There, I am Sofia Carter. There are numerous reasons why your HP laptop won't turn on anything that occurs when you click the power button, your laptop lights come on but your screen doesn't, or your computer displays an error message on a black or blue screen, among others. In general, if your laptop's battery is depleted or broken, and it can't deliver battery power to your computer, your laptop will not turn on even if you click the power button. External gear and your computer system can sometimes cause problems, resulting in your laptop not turning on.