You should have a Prt Scr button, either by itself or as a secondary function on another button, i.e. FN+Insert or something similar.
Anyhow, the Prt Scr function takes a screenshot which you can then paste somewhere else.
Also see http://windows.microsoft.com/en-ph/windows/take-screen-capture-print-screen#take-screen-capture-print-screen=windows-7