Most of people know about Print Screen button in keyboard. It works like a camera. We can use this key to obtain screen capture. It can be a powerful tool if you know about this great tool.
How you'll do it :-
Press Print Screen Button from your keyboard & paste it (Ctrl+V) wherever you want the screenshot to appear.
Print Screen with Alt
This is different from that it takes screenshot of the currently selected window or dialogue box. It doesn't take entire screenshot. You don't need to crop image. Suppose you want to save a workbook in excel, obviously you will press Ctrl+S. After pressing this key a dialogue box will appear & you want to take only its screenshot not entire worksheet. So you need to do...
Press Alt + Print screen (but first press Alt then Print screen key) then paste it where you want.