Have you ever had a problem with your computer and received one of those error boxes that has some strange message with a long error code? Wouldn't it be cool to grab this screen to show to a friend or tech support at work? Maybe you found a totally cool picture that you want to share with a friend, you can copy it right to your graphics program or Microsoft word by using the Print Screen or the PrtS key.
To capture the whole screen, just hit the Print Screen (it might say Prt Sc) button on your keyboard.
Then, open your imaging software (and a blank page, if you need to - it will depend on your software) and select your "Paste" command (usually Ctrl+V).
This should paste an image of your computer screen into the document you're working on. You can also paste the image into a word processing program like MS Word or WordPerfect if you don't have imaging software. (With Word 2000 and newer, you might need to have the program open before you hit Prt Sc for the screenshot to go to the clipboard).
If you would like to capture only the current window, hold down the ALT button while you press the Print Screen button.