I've just changed the battery today, then the radio doesn't work. I don't know the radio code as well. what should I do?

Hi

a dealer should be able to give you the code if you get the serial number from the radio, also are you sure the code is not in with your car books, service manuals and book packs, often it is in there o a small credit sized card. alternatively some radio decoders will come to you at home, they charge about £25 in the UK to recode the radio.

Hope this helps
Regards

Dan