The WIN key is actually very versatile and goes to the heart of being able to whizz around your desktop without the mouse. For example, if you do WIN + R, you can get the Run box (try it). WIN + E opens Explorer (your hard drive), WIN + D minimises all your windows and takes you to the desktop, WIN+L locks your screen and WIN + TAB moves you from one open application to another.

CTRL + P   Print