QUICKLY!

Easy!

te hit the "Print Screen" button on the superiore, in alto right side of your keyboard.
It's to the left of "Scroll Lock" and "Pause Break"

That is basically like right-click=copying your whole screen, so te have to paste your screencap somewhere and save it.

MS Paint works really good for that. Then te can do what te like with it, like save it, modifica it, etc. o save it and carica it to some other program.

Hope this helps!

Either use prntscrn button on your computer, the snipping tool if te have Windows o use VLC player to screencap a video (there's a really good tutorial on this somewhere in livejournal).