The best, and safest way, to power DOWN your PC is to first use a Quick Shutdown shortcut on your desktop, or Task Bar. (also called a Quick Launch toolbar)
Here's the text for the best and fastest Quick shutdown shortcut.
%windir%\System32\shutdown.exe /s /t 1
Then once you have the pc powered DOWN, remove the line power from the PC.
Most PC's are never really OFF, just the OS is shut down....the PSU is still running to provide power to the Power ON switch and several circuits on the motherboard. Several things can turn the PC back on without your intent or permission.
You should have your PC plugged into a switchable power strip, so you can totally turn OFF the power to your PC when you don't want it ON. Your monitor should also be plugged into that same Power Strip.
I've done that with my own PC's for decades and I try to get all my PC customers to do the same.
(I've been in the computer business since 1980)
You don't really need a Computer Engineering degree to operate a PC in an educated manner. Just a little common sense goes a long way.
Good Luck and Happy Computing!
TechnoMage 