I have been 'waiting' a long time...

Recently the battery in my car was replaced. In the process, my stereo was disabled. My owners manual had the correct code written on the inside flap(I'm the second owner). The screen read 'code' until I punched in the code and then the word 'wait' flashed on the screen. Well I've been waiting along time and nothing has changed. I repeated the process several times, no change. What do I do??