new battery will not allow the log in to happen

I have an iPhone 4s with a battery that was losing charge in an hour or two of use. I picked up the battery kit with correct screwdrivers and the correct model 1387 battery and installed the battery. with the new battery the iPhone will turn on but will not allow the log in to happen. At first I thought I did something wrong because there it was searching for a network instead of being connected to the network we have. So I proceeded to charge the battery and hard reset. Still is not working. I put the old battery in and it works fine now. Any ideas?