iPhone 4s screen not working after replacing a few times

So it all started with the basic cracked screen. I had changed a few out before so figured it was no problem.

1st, the screen was working fine after I replaced it, but the home button was a little sticky, so I open it back up and fix that an then put it back together. I turn the phone on, and realize that the power/sleep button isn't working, so back open it goes. I realize that I made a dummy mistake and the ribbon cable for the sleep button got under the board.

I put it all back together, and its working fine. Then, I notice that the screen is not flush with the frame (I had to switch frames since I accidentally bought the wrong one) which was the easiest of all these steps. Just put down some 3M and reseat. right?

Wrong.

I put it all back together and now there is no display on the screen. I know its not the screen...

I know this because I have 2 phones broken down right now. I took a cracked screen from another phone that worked but was just cracked. The screen worked on that phone, but not this one. Same with the original cracked glass from the phone. Only very dim backlight with no display.

I tried all the reboots, resets, and restores. Still nothing... cleaned the connecters on the board and screen, nothing.

Nothing seems bad on the board but I don't know how to tell for sure.

The screen turned white for a second earlier, I thought it might be a sign of life, but now its right back to dim backlight.

PLEASE HELP!!!! I stayed up until 6am trying to figure it out.