iPhone 4s won't charge/turn on after screen replacement.

Hey!

I hope you can help. I recently dropped my iphone, ordered a new screen and LCD replacement.

All was good, I was very very careful and organized when taking it apart and reassembling the product.

After I was finished, the phone turned on and was working perfecting. I plugged it in, like I do every night only to realize that in the morning it had not charged at all. By the time I unplugged it and went downstairs, it shut off and continued to reboot.

I then opened the phone back up to inspect the dock connector cable, battery connection etc. Nothing was flagging as incorrect.

I read some info on restoring the phone, as this seems to be a common problem. Well, this then brought me to my next problem, the phone is not able to restore and update due to error 21 (hardware issues).

When I plug the phone into the USB port of the computer the itunes connector symbol appears, but this also happens when I plug it into a wall adapter for power.

My hunch is that the main problem in the charging of the phone, but I have no idea how to fix this!

Please help!