The Windows key can be used in conjunction with other keys to act as a keyboard shortcut for faster access to menu commands. Now, while the Alt key tends to open program menus (ex: Alt+F opens the File menu and Alt+E opens the Edit menu) and the Ctrl key performs actual operations (ex: Ctrl+C will copy and Ctrl+V will paste), the Windows key will open various Windows tools...
Win key + R will open the Start menu's Run box
Win key + F will open the Start menu's Find window
Win key + E will quickly launch Explorer
Win key + Pause/Break will open the System Properties window
Win key + M will Minimize all windows
Win key + Shift + M will undo Minimize all windows
Win key + D will switch between minimizing all open programs and showing them all
Win key + Tab will cycle through items on the taskbar
Win key by itself will open the Start menu
You can also open programs or folders on your desktop by pressing the Windows key + the first letter of the program/folder/shortcut + Enter . Sounds kinda tedious, but if you're in a bind with your mouse, it can come in quite handy.
