Replaced screen assembly, screen still black, including backlight

Hi,

My front panel was seriously damaged yesterday. When I connected it to my computer I could still see it properly on itunes and I managed to get a backup immediately.

The backlight used to turn on even though the screen was completely destroyed and had pieces fallen out.

Today, I got a new front panel assembly (inlcuding home button earpiece etc...).

I put everything back and connected the cables.Cable 1 seemed to be a bit on the loose side first but i managed to keep it in place while closing the screen onto the housing.

To my surprise, when I tried turning my phone on, nothing seemed to happen. So I connected it to the charger, and it made the usual sound.I tried the silent switch, and it worked fine too.(after this, I unplugged everything and plugged them back in a few times and checked again and again.But nothing changed.

Finally I connected it to Itunes, that worked fine.

Now I'm letting it do a complete restore, and I'm afraid nothing is going to happen...

What could be the problem? Could it be something with the display driver on the logic board that's not possible to change and repair?