Windows screen get turned sideways–how to fix it?

Sometimes users get puzzled, because their Windows screen on a notebook get turned sideways. Why is that and how can this be fixed?

I read this question from time to time within forums. While a tablet pc can rotate the screen, depending on the device's orientation, on notebooks this isn't normally the case. Here some key combination pressed accidentally is the root cause for a screen get turned sideways.

In case, you get this, press  Ctrl + Alt + UP Arrow Key, or try Ctrl + Alt + and a different Arrow Key. Also a right click to an empty place on your desktop opens the context menu. Select Graphics Options > Rotation to open a page that allows to rotate the screen back.