Problem booting after new battery replacement.

I need some help. I just replaced the battery from ifixit and did all the steps perfectly. After I got the phone back together I tried turning it on to see if there was any charge left in the battery from the factory, which there wasn't. So I plugged it into my charger and it booted up into the apple logo, then about 5 seconds it shuts off to a black screen then Immediatly boots back into the apple logo - This will go on for hours.

I pulled it apart again and made sure everything was done right, and the dang thing keeps doing it. I tried putting it in DFU made while connected to my computer and it registers in iTunes but there is NOTHING on the screen of the iPhone.

Nothing is working, please help :(