I have a 2000 Honda Civic and my battery has recently been removed and the radio...
 

...is locked. Help!? The radio says Err.

get the manual and see if there is a reset button. I had the exact same problem with my civic, or any car for that matter.































it might need to be reset and for good measure you might want to check the fuse console (under the steering column). I had my battery replaced and a fuse blew in the process and for the life of me I couldn't figure out what it was! I was ready to sue the garage b/c I thought they busted my 300 car radio!