There may be a setting in your display driver control panel
example for my NVIDIA
No that's not what I meant. Because the way my room is set up is that my piano is on one end of the room and my computer and monitor (TV) is at the opposite end. I have a mirror above my piano for which I can see the monitor but since my mirror makes all text on the computer unreadable it kind of screws me over. So I'm wondering if there's a way to configure my monitor so I can read text/music notes from my mirror.
I don't believe this can be done. Besides, the idea is absurd. It would render the screen unreadable. Are you trying to play a trick on somebody or what?
It's not absurd, just thinking outside the box.
The only computer I have is a desktop, nice try though.