Volkswagen: 95 Passat GLX radio, code radio, prevention system

Question
While there are numerous electrical problems it seems, I recently replaced the battery in my Passat GLX. Now the radio will not reset to "Safe" mode or anything else. The red security light blinks, but the face is completely blank.

Any suggestions as to what may have caused this and how to solve it??

thanks,
Bill

Answer
In your service manual, or radio manual, there is a card (looks like a credit card) that gives you a code number to turn back on the radio.

It is a theft-prevention system.  

1) Find the code
2) Put the key on "on"
3) Type in code

Radio will go on.