To capture your entire screen and automatically save the screenshot, tap the Windows key + Print Screen key. Your screen will briefly go dim to indicate that you’ve just taken a screenshot, and the screenshot will be saved to the Pictures > Screenshots folder.
Windows 7/8 PC:
To capture your entire screen, tap the Print Screen (sometimes labeled PrtScn) key. Your screenshot will not be saved as a file automatically, but it will be copied to the clipboard. You’ll need to open an image editing tool (such as Microsoft Paint), paste the screenshot in the editor and save the file from there.
Press Shift+Command+3 to capture the entire sreen and automatically save the screenshot to your desktop.