You should try connecting an external monitor, and see if it will work. If the computer screen does not automatically display on the external monitor, press F4 (or the key with the monitor(s) looking symbol ) until the screen image displays.
If you get an image on the external monitor, then you should try going to the Lenova website and see if you can get, and install, the latest drivers. Then restart the computer, without the external monitor attached, and see if your screen is working again.
Also, you can try taking out the battery, and make sure the AC adapter is disconnected from the laptop & electrical outlet.
Then press the power button 10 times. Press it one more time, and on this 11th one, hold the power button down for...