question about a samsung propel phone?

i have a samsung propel and it had gotten water damage but it dried out or whatever so now it turns on and if i turn it on without the sim card in it give me that message saying put in the sim and i click the buttons and they work and i can exit out of the message box so the buttons work fine then. when i put in my sim card (because im exchanging phones and this one is used) none of the buttons work except for the call button. when i put my sim card in a different at&t phone everything is fine. this propel has been just sitting on my table for a few months turned off and everything seems to work im really confused does anyone have any advice? i will choose a best answer.
now the buttons are working, they are kind of slow but they work is it like warming up or something? im so confused im technologically impaired