You could also find the code in the wheel well under the flooring in the hatch. In "
MOST" cars there is a Radio Key sticker next to the options sticker. Now I say MOST because my car did not have this sticker.
I had to go to the Dealer have them pull the RAdio and get the Serial from it. Call Volkswagen and lookup the key. $60 procedure :P
If you know where the Dealer is that sold the car when it was new they should have the Code in their records. Some will give it to you right over the phone others will want you to be there in person for security reasons.
01-02 cars have radios that usually reset themselves when the power goes off. As long as neither hardware the car or the radio are the same the Radio preforms a "handshake signature code" with the car. If it's the same it comes right back on without code. If not it requires code.
But..... sorry for the long trip
fatdaddy mentioned NOthing showed up on the display. So I would say the guy that installed the radio hooked it up wrong. I have not replaced my stock radio yet. so I don't know the specifics on that. Hope you get it working again