Will not boot, gray screen.

Recently, I broke my screen. So, I bought a new screen to replace it. The screen lit up but it was gray and all the normal booting sounds were there but the screen was still gray. I tested the new screen on someone else's laptop and it worked just fine.

I figured it was probably the video cord, so I replaced it. Same result.

What is wrong with my computer? Why is the screen gray and why does it not show any image on my laptop?

Ps. I changed the ram and still the same result. I cleaned all the ports for the ram and hard drive, same result.