There is a "cracked" sceen/display, how can I fix this?

One time, my brothers were using the laptop, but than it suddenly broke. The screen itself is not cracked, but it looks like the display is instead. It has never improved, but instead it has only gotten worse, slowly. With the many cracks there are many colors (black, pink, purple, grey, etc. in some spaces, and there are many blacklines as well) and when the mouse reaches the bottom of the screen, it goes back to the top. It's been like this for three years or so, and I am losing patience! Please help! Thanks for your time.