Computer Question: The light on my computer will not stay on. Any ideas on a fix?

Hello. I would first like to give an apology because I know computer questions can be “annoying”. However, I thought I would try here before going elsewhere. May I offer one more apology? The wording of this question may be a bit off as I don’t really know the proper language.

This is a laptop.

Explanation of problem: When my computer is on there are two lights in the front of the keyboard (down below the clicker space). When both lights are on the icon in the task bar shows battery as full and a plug near it. Also my screen is bright. When one light is on then it just shows the battery. Also my screen gets darker. Now when I’m using my computer sometimes one of the lights goes off/screen gets darker. If I tip and tilt the computer it will turn back on/screen get brighter.
Any ideas on what the problem is?

History: We were having this problem previously and eventually it wouldn’t turn on at all. We got a new cord for the computer and it turned on with no problems so I thought perhaps because the old cord was frayed that was the problem.

So I am wondering if we are still having same problem or if it is normal if computer is tilted wrong way for the “light to go off/screen to darken”.