Stock Stereo Problem

Had a battery replaced in Volvo S70. Now when i turn the car on the stereo display reads "OFF", but the antenna goes up. If I press the power button, the display reads nothing and the antenna goes down. No workie =( Anyone know anything about my problem?

Nevermind. For some reason it's acting like i already tried putting in an incorrect stereo code. I have to leave the key in the accessory position for 2 hours until it resets. Thanks to those of you who considered responding. :\