Making a screenshot on Windows is pretty easy and you don't even need to install any additional software to do it. Just follow these simple steps:

1. Press the button "Print" on your keyboard (top right on most keyboards)
2. Start Microsoft Paint (click Start > All Programs > Accessories > Paint)
3. Choose Edit -> Paste in the menu. The screenshot should now be visible there in Paint
4. Click on File -> Save in the main menu of Paint to save the file on your PC. Suggested format is JPG (a.k.a. JPEG)
5. Send the saved file to us via our support helpdesk

Further information: http://en.wikipedia.org/wiki/Screenshot#Taking_screenshots