My screen is black but there is light in the

My screen is black but there is light in the background. I am not sure what to do because it turns on but I am not sure what buttons I am pressing. Before this I was having screen problems where there were rainbow colors going and coming. When I slid the keyboard up the screen would be all glitchie and not proper. If I touched it in the correct places I could go where I wanted to go. Could someone please help me.