Option Command PR does not work on my MacBook Air
I've read several "answers" in relation to this problem, and they all say pretty much the same thing: "To do a factory reset, press Option Command PR on startup" - which is intuitively obvious, because I know that's the key sequence I want, (I've done this many times) and it's what I was trying to do, and it didn't work, so I asked for solutions.
Does anyone know the answer to the problem I'm having?