Audio Systems: Car Stereo Not Working, 2000 mitsubishi galant, mitsubishi galant

Question
I drive a 2000 Mitsubishi Galant with a factory stereo.  I just had the car repaired with a new timing belt, balance shaft belt and crank sensor.  I also had a new starter installed.  When the car was returned to me, I turned on the radio and the word "CODE" appeared on the face.  I fiddled with the buttons and received an error message.  And now when I turn on the radio the word "OFF" appears on the face, and nothing plays.  Do you believe that this is due to the anti-theft device, and what measures need to be taken to resolve the problem.  

Answer
Hi Brian,
Skip the first two sentences and substitute for " battery was disconnected”, That’s why the word "code" popped up and at which point you should have looked in your cars books and found the radio code, (sometimes on a card)and following the car radio's instructions entered the correct code. if you "fiddle" with the code / buttons too many times it locks out and then has to either go to a dealer to be unlocked and re-set or you have to find a unlocking code and unlocking instructions. Both can be found for a couple of bucks on eBay, just punch in "radio codes" and a dozen will appear, see if there is a “Gallant” one or a general one that will work.
Hope that helps but it seems you have shot yourself in the foot.
Peter