Why is my screen not turning on but all the lights to laptop are?

It is possible that your display either failed or the back light has failed. The best way to test this is using an external monitor, if you do not have one then check with friends and family. If the display works on the external monitor then the problem is in the laptop display, if it does not work on the external monitor then the problem is a bad graphics adapter on the mother board.

If the external monitor displays properly, try shining a bright light on the laptop display to see if you can see any icons or the desktop, if you can see icons then the problem is the back light is defective. If you do not see anything then the display itself is defective.