This issue can be caused by a couple of different parts. It can be caused by a bad LVDS cable (video cable), a bad LCD, or a bad logic board. The time and money that you will spend, unless you have another same macbook pro, is not worth it. You may just considering using it as a desktop with an external display, keyboard, and mouse. Apple offers a flat-rate option that would repair this problem for around $300-$400 but this model is too old for that option. Another option is to go online and buy a used macbook pro, you can find a comparable one for around $300-$400. Apples refurbished computers are also a good deal. Hope this helps!