Why is my replacement screen not working?

My Acer Aspire 5733z-4851 screen was broken. A friend of mine has gotten the replacement screen and put it in. He turned it on and it's just white. No logo comes up or anything. Is there a problem with the screen just not being recognized or is there a cable connection problem? Something tells me that it isn't that big a deal, it's just an easy fix but I thought I would get an expert opinion. I need my laptop back:(