I cant unlock my kvt-617dvd

Find the person who u bought the unit from either they set the code or a person did who they got it from, it should be a 4 digit numbered code, if you can't get the code u might as well use it for a paper weight. if buying a kenwood used the best thing to do is tell them you want to see it hooked up and running or I won't buy it. the very first screen that appears is the code entry if the code has been set. if the code hasn't been set, this screen should not appear. do this asure yourself, i do.