iPhone 2G Battery Replacement HELP!!

Hey Guys,

Today I replaced my iPhone 2G Battery (the old one was faulty) and it works fine. I have a big problem though, It wont charge or respond in iTunes:

So when I plug it in via the USB cable, nothing happens, It doesn't show up in iTunes, or say that it is charging (The Battery is running low!), also the home button doesn't work, So I cant go into DFU Mode. I got the phone about 2-3 weeks ago off ebay from the US, it is locked to AT&T so because I cant even plug it in to the computer, there is no way I can unlock it and use it.
PLEASE HELP, Thanks in advance.

Josh,:mad: