Audio Systems: Automotive Electrical Short, dome lamp, lamp bulb

Question
Went to replace a non-working dome lamp bulb and now dome and radio do not work.  How do I track down the short?  One weird thing: when you open the driver's door, for that split second when the pressure switch in the opening door is just about to be free of the door, the radio will come on.  Any advice?  

Answer
Hi Larry,
Always back pedal to the last time everything worked. remove the dome light bulb, any change? If so check what you could have done wrong. No change? check power with a tester,(bulb on a wire will do) meter or 12v probe, check all fuses with a meter as hairline breaks are hard to see. apart from that. I cannot think of anything without being on the spot myself.
best of luck, Peter