The code is usually printed on a card that came with the car. If you don't have the code, you can contact your local Seat dealer.
Once you have the code, follow these steps to unlock the radio:
1. Turn on the radio.
2. Press and hold the preset button 1-4 until the word SAFE is displayed.
3. Enter the code using the radio buttons.
4. Press and hold preset 1-4 again until the radio turns on.
If the radio still does not turn on, you may need to have it repaired by a qualified technician.