As of right now, I am using two iPhone 3G's, but both screen won't work at all. I've noticed that the problem isn't the actual screen, I think it's the logic board (I think that's what it's called?) where the camera, SIM tray, etc. where all the connectors (1-6) connect.

It all started with my first iPhone 3G, which is a white one. I took it apart because I was replacing the back cover (for obvious reasons, it's badly scratched) and as I put everything back, EVERYTHING will work except the screen. If I plug it into the computer, I will hear the beep thing, so I know it's on. And I switched the vibrate button up and down, so it vibrates. So I know it's on for sure.

I got upset because I didn't know what the problem was, and I kept searching everywhere. So I took apart my other iPhone 3G (black) up to the logic board. Which means I basically only took the screen off. I connected the black iPhone 3G screen to the white iPhone 3G but it didn't work as well. So I did vise versa (white iPhone 3G screen onto black iPhone) and it worked.

In my mind, I thought, it couldn't be the screen then, so I took out the logic board of the black iPhone and switched it with the white iPhone. Now both doesn't work.

I really don't get what I did wrong, and I am so upset and confused. BOTH the black iPhone and white iPhone screens won't "show up".

PLEASE HELP. ANY suggestions are appreciated.

(The black iPhone is my brother's, so if I don't fix it, my brother won't have a phone either.) :/