How do you take a snapshot of your current screen on the computer ? useful for creating tutorials.?

For Example if I wanted to show someone what my screen looks like at the moment what would I use to take the picture. Asides from an external camera.How do you take a snapshot of your current screen on the computer ? useful for creating tutorials.?
Press Print Scrn and paste into an image editor. If you want to capture what your doing on the screen as a video you can use CamStudio free.





CamStudio is able to record all screen and audio activity on your computer and create industry-standard AVI video files and using its built-in SWF Producer can turn those AVIs into lean, mean, bandwidth-friendly Streaming Flash videos (SWFs)

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