Try unplugging the unit for 60 minutes, then plug back in and try it again. This will reset the processor and hopefully the unit will operate normally. Check all the speaker wiring for shorts, make sure they're also not touching the chassis of the receiver, or are not otherwise pinched or frayed. If all looks well, try disconnecting all the speakers and cycle the power off, then on again. If the unit shuts down with no load connected, fails to power up, or if you have "protect" on the screen, then the unit likely has a bad output transistor, or capacitor and is in need of service. I can send you the contact info for a Service Center near you if you'd like.
If this answer solves your problem, please click "Accept". Tips and Bonuses are always welcome and appreciated!
Tried all the above with no success, do you have the part number for the output transistor, or capacitor