Audio Systems: 04 chev radio oe locked, chev trailblazer, salvage yard

Question
i  have  a  2004  chev  trailblazer, with a   oem  cd/ cassette  radio  in it.  someone has  stolen my radio. so i went to a loacl salvage yard bought a used  radio, but we cannot get it unlocked,  can you help

Answer
Sorry, Rick,  but if you read my profile you'll notice this is not my area of expertise, especially compared to other "Car Audio" specialists like Garrry.
 I would encourage you to try one of them or check back through previous answers as this topic comes up VERY frequently.