So, for all you PC users out there - I found this article. You may want to take a couple of minutes reading it?
It looked quite helpful to me. Particularly using the Snipping method - which enables a screen shot of just a section of the screen, rather that the whole screen
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Section of screen 'grabbed' from my Mac screen.
Click here to read all about it: http://www.wikihow.com/Take-a-Screenshot-in-Microsoft-Windows