thanks steet for your help and same with draco

It may not work correctly with videos though, because of overlay : in that case, you will need a special program like Screen hunter (which is free) or HypersnapDX, for example.

To take a screenshot, for a PC/Windows computer, make sure the screen is showing what you want to capture (if a video/movie image, make sure it is on pause) then there's a button up on the right corner of the keyboard that has print scr written on it. Push it.

Nothing will seem to happen, but now you need to open an editing program like MS Paint (most windows come with it) and go to 'edit' 'paste'. Then the screenshot will come up. Then do what you want, draw on it, crop it, etc. then save it to your computer.