Re: Pah!
She'd had to use the mouse upside down but was so worried about being yelled at had kept quiet.
...
No, if she had turned the monitor upside down the mouse would work normally.
No, it wouldn't. If you move the mouse from right to left, it goes from left to right on the upside-down screen. And if you move the mouse up, it goes down on the upside-down screen.
Turn the mouse over too, and all works OK. Though how you press the buttons is an interesting question in itself.