Audio Systems: Receiver Problem, lightning strikes, amp section

Question
On and off for the past few months, I hear a popping sound coming from my stereo speakers.  Sometimes it goes away and at other times, the stereo will stop and "Protector" will flash on the receiver.

Best Buy told me to replace the speakers.  We swapped out the speakers for others and the problem continued.  We even changed all the wiring and replaced the outlet plug which was loose.

For a few weeks, it worked and now it's back to not working at all.  When you turn on the receiver now, it won't even tune in a radio station.  It goes right to Protector.  We have not had any lightning strikes and everything is plugged into a surge protector.  The receiver is 10 years old.  

The manual tells me it's probably a short circuit.  I'm not sure what to do with it.

Thanks.  

Answer
from the way it seemed to start, i would first look for poor solder connections. just look all over the board, not just the amp section or power supply sections, which is where i'd look first. you didn't tell me what brand, if it's a high-end model or not, so taking it to a shop will be your decision. it probably won't run more than $100, unless there's more wrong with it. good luck.....