what should i do if my lenovo laptop is not turning on. when i pressed the power button on it working normally until lenovo is

Aug 2, 2018
when i start the laptop the power on light is working but its displaying only lenovo in background, its not even showing the windows ,its taking hours to turn on sometimes even then it is not turning on. This problem is repeating while shutting down the power light is not turning off even after 10 minutes after i shut down.