I am a new owner of a vintage MacPro1,1. The Mac Pro is in good shape and passes the Apple Hardware Test without problem. I recently observed a strange behavior about how the Mac Pro self-powers on after shutting down. Here is the situation: If I shut down the system from Mac OS X, it shuts down normally. I then turn off the power bar to which this system is connected. When I turn on the power bar later, the Mac Pro stays shut off until I press the power button to start. This is what I expected as NORMAL BEHAVIOR. Now, if I manually shut down the system by pressing power button at the boot screen (by holding down the option key), the system appears to shut down normally. However, if I then turn off the power bar to cut power to the system but then later turn on the power bar again, the Mac Pro automatically starts up without me needing to press the power button. Is this NORMAL or ABNORMAL? By comparison, I tried this scenario out on my friend's MacPro5,1. The above does not occur. The Mac Pro just stays being powered off until the power button is pushed. Is there some non-volatile system parameters I need to reset? I reset the PRAM and SMC already. Please help!