Screen blank since stripped out motherboard and left for a few days

Hi guys

I hope someone can help me I have an iphone 4 and I have just replaced the iPhone 4 Proximity Light Sensor Motion Flex but I had to wait 3 or 4 days for a few screws to arrive. I reasembled it all back together but all i have now is blank screen with a back light. I tried to reset by holding the home button and power button but still no joy. I could really do with a but of guidance here guys........ and it occasionally vibrates too.

I have read a few other fixes but none that are for the iPnone 4.

Should I do a restore from iTunes or....... ahhhh what should I do next ???