Switched batteries, now phone wont turn completly on???

[lauradenise]

Hi guys, Well, i recently got my hands on a battery that a friend no longer needed. So i used it last night, Phone worked Great! I charged it fully...and went to put in my battery and the eris turns on, so you see the little android guys, then the HTC screen, and then Verizon wireless comes across....and then it stops...it stays on that screen for alittle bit, and then goes back to the HTC screen. We've both got our phones about two months, so the batteries aren't OLD. Can someone PLEASE help, i really enjoy my phone..and would just like to have it working again without having to send it in!! Thanks...