Back in the day...
When PCs had proper on-off switches I had a user call in a panic late one afternoon.
User: "How do I turn the computer off?"
Me: "Did you turn it on this morning?"
Me: "Well press the same switch!"
User: " I know that, but which one is it?"
The PC was an HP Tower with a white on-off switch in the top corner so fairly visible*.
*Unlike an Apricot PC I installed where the on-off switch was a grey rectangular push button in the middle of the back that looked just like a cover over a port.