If you have a multi-meter, check the voltage of the battery. If it is less than 12V (this voltage works for CD/radio), then jump start your car and run it on high way for 20 minutes after starting. If the voltage is ok (e.g. more than 12.5V), then the battery is ok. Think about the electrical circuit, e.g. fuse. Another possibility is the problem of security feature if your car has.