Welcome to the forum!
Let's see if we can relieve some of that frustration.
What system do you have?
My first guess is that one or more of your speaker wires is bridging across the gap between the speaker terminals (on either a speaker or on the receiver) and is causing a short circuit. This would cause the receiver to go into a protection mode and mute itself.
Does anything show on the front display of the unit when this happens?
