Ctrl + Esc

Open the Main Menu.

You can customize this keyboard shortcut. 

Windows logo /Diamond + R

Open the Run Application dialog.

You can customize this keyboard shortcut. 

Print Screen

Start the screenshot application and take a screenshot of the entire screen.  

You can customize this keyboard shortcut. 

Alt + Print Screen

Start the screenshot application and take a screenshot of the window that currently has focus. 

You can customize this keyboard shortcut. 

F1

If the focused element is an application window or dialog, this keyboard shortcut opens the Help for the application. 

Ctrl + F1

If the focused element is a panel or application window, this keyboard shortcut switches the display of tooltips for the window or panel objects on and off. 

Shift + F10

Open a popup menu for the element that has focus, if a popup menu exists.