* The radio is simply not getting power: Check your fuses. The radio usually has its own fuse in the fuse box (under the hood and/or inside the car). A blown fuse will prevent the radio from turning on.
* The radio is locked due to a security feature built into the vehicle's anti-theft system: This is less common on factory radios but *possible*. It usually involves a specific sequence of button presses on the radio itself or a combination of actions with the ignition system. Your owner's manual should detail any such procedures. If you don't have the manual, you might find a PDF version online via a search for "[your vehicle's year, make, and model] owner's manual PDF".
* The radio is malfunctioning: This could be due to a number of internal problems.
If you've checked the fuses and don't find any security procedure described in the manual:
* Consult a professional: Take your car to a qualified car audio installer or a Pontiac specialist. They will have the tools and experience to diagnose the problem properly. They can also determine if a repair is feasible or if a replacement is necessary.
Important Note: Avoid attempting to force the radio out or tampering with the wiring yourself unless you have experience with car audio. You could cause further damage to the vehicle's electrical system or the radio itself.
