Oh I understand what you mean I think
You want to take a screen shot from a video that you have right? Yeah the "Print screen" button doesn't work lmao. It's really weird but eh. Of course it's possible to do ^.^. I do it all the time for my miniclip graphics and such.
The way I do it is like this -->
You need a program called "Virtual Dub" which you can download for free at
http://www.virtualdub.org/index. Download it and install it. When it's done, open up the actual Virtual Dub program, then go on File -->> Open, and open up your video clip (Your video has to be in .mpeg or .avi format. If it's windows media or real player, you need to convert it with a video converter, or try and get it in a different format, otherwise it won't open). It will then open each individual frame in your video, just scroll across to the part of the video that you want to screen shot, then press "Ctrl" and "1". This is the equvilent to a screenshot actually lol. Then open up paint, or any other image editing software, and paste (Ctrl V) there and it should come up without the video still moving lmao xD! Crop it and there you go!
Hope that works, if you're having trouble with this, lemme know lol. :thumbsup: