Hi Yvonne, you will have to remove the radio and find the serial number should look like M123456 it will be on some stickers and engraved into the side, to remove the radio you need to push prongs into the four holes in the front of the radio, you can buy the correct tool from halfords but you can make your own if you cut the ends off a wire coathanger they are about the correct spacing push them into the holes and with a bit of outward pressure you can then pull the radio out its easier with a second person, when you have the serial number re ask for a code and you will get it here for free!
nigel, May 2008