maybe the Altinator or crossed wires Check Your fuse box
I had to take mine to the local Chevy dealer to get the code to reset the radio after the battery was changed. I was charged $40 by them to do this.
I actually own a 1984 Chevy celebrity and it took me 8 hours to take the dash apart, install the radio and put it back together again. Then, my radio stopped working after 2 weeks. If you want to take on this task, you will need to start by removing the screws from inside of the glove box. My advice: just don't. If you are half as stubborn as me, you will not listen, but you have been warned.
check your fuses
It's a wild, shot in the dark, but I'd guess the one marked 'RADIO'. However........the fuse for the courtesy lights can also kill a radio. At least it does on my '88 Celebrity Wagon.
Unhook the car battery.
I had to go to a dealership to get the radio unlocked, also the cause; ( radio locked) was Battery Failure. After I puchased a new battery I found the radio use to be locked.
First check the fuses.
reincarnate your battery dudes XD
The battery has been disconnected. You will have to reenter the radio security code to reenable it.
You know your car has blown a fuse if whatever the fuse is for suddenly quits working. For example if your radio is playing and for no reason quits it may be a fuse has blown.
Every time you disconnect a battery cable you have to reprogram the radio stations ( if that's what you are asking )
To install a Cobra CB radio in a 2010 Chevy Lumina, first disconnect the battery cables. Then mount the CB box and then power the CB radio. Then mount the antennae.