How do I rotate Windows 8 screen?

Solution 1:

Right-click the desktop and click Screen Resolution.
You will then see an Orientation dropdown:

Solution 2:

To rotate the display, hold down ctrl+alt and either Up, Down, Left, or Right to orient the screen as each of the four orientations.

Solution 3:

"Orientation" setting is sometimes removed by computer manufacturer through modified drivers. If there is no such setting on your notebook, try installing driver from graphic chip manufacturer (Intel, nVidia or AMD) instead of from your notebook manufacturer.

Eg: HP 250 G2 notebook was missing this setting. After HP-supplied driver was uninstalled and replaced with authentic driver (obtained directly from Intel website), the "Orientation" setting appeared, as on SLak's screenshot.