Another funny issue encountered by a client was that her laptop screen got side flipped (to 90 deegrees).
This is triggered by a hotkey or a key combination. Don’t ask me which one, but I will tell you how to fix this.
Right click on the desktop, “graphics options”, “rotation”. Select “rotate to normal”. This should fix your issue.
I’ve noticed that this option exist only on my laptop, and not as well on my desktop PC. The laptop has an integrated Intel HD 4000 graphic card with a dedicated ATI Radeon video card. I’m not sure if this rotating option comes from the ATI video card software or the integrated one.