2001 Saturn radio reset after battery change

Question

My girlfriend had the battery replaced in her 2001 Saturn L100 a few months ago. The factory radio has not worked ever since. I verified that it is getting power, as the the clock works and the display lights up etc. I read & followed all the steps in the owners manual and I get an ERR1 message on the display. She has not set the theft deterrent feature on the radio. She said it happened once before when she went for service a couple years ago. She said she took it back to the shop and they did something quick to get it working again.