>im suprised none of you can give a decent answer
Maybe they have better things to do today.
I'll post something, if incorrect that will bring them out. There are things better, but this could probably make you happy enough.
Second one probably better, as you may have the 12v but may not have the 5v, which would turn on the device. If the switch is using the same supply, then if there is power for the device, there is power for the switching transistor to turn off the mosfet by default. A pin is high impedance by default so will take an active piece of code to make the pin low and turn on the mosfet via the npn.
Or something like that.
You should get some kind of simulator software so you can try things out, and not have to always rely on others. Others can point in directions, and can be useful, but ultimately its better to learn to fish than be handed fish.