On a Windows system with a full-size keyboard:
- Press the "PrtScn" (Print Screen) key to copy the current screen into the clipoard
- Start Paint (under Windows Accessories in the Start menu)
- Press Ctrl+V or select the Paste button
- If desired, use the crop tool to select a specific area of the screenshot
- Save the picture in the PNG or JPEG format
On a notebook keyboard it may be necessary to press a "Fn" (function) or similar key together with the print screen key in order to achieve the desired effect.