Laptop screen flickers and is unreadable

I have a Dell XPS M140 that my brother was getting rid of. The screen is one blank color with flickers running through it from time to time. I think this may have happened to to his habit of carrying the laptop by the screen. It works when connected to an external monitor so i know the video card works fine. The color is similar to the color of whatever is supposed to be displayed so I know it is trying to display something. Another interesting fact is that the scren works perfectly when pushing down on the upper left corner of the screen. different spots in the corner work either better or worse but all of them block some part of the screen if you try to hold them down or keep something there to put pressure on it (my brother's temporary solution, unfortunately the the position of the spot needed to be pressed has somehow shifted down away from the top of the screen). I know pushing on it is bad for the screen and would appreciate it if someone could try to help me figure out a way of fixing it without getting a new screen. I have tightened all the screws inside and outside the laptop's top cover and checked the wires connecting the screen to the base. I may have missed something as I am not a laptop expert.

Thanks,

Reffu

I would but on the back of the display where i would have to put something is the screen's motherboard(or whatever it's called) it has a big piece of plastic covering it that says do not touch. thanks for the suggestion though.