Your original files no longer exist. The only exception to that statement might be if you've deleted them from your hard drive (or external media, such as a USB memory stick) and your computer hasn't yet over-written them. If so, the free version of Recuva should be able to retrieve them:
https://www.piriform.com/recuva
You could use Windows Live Movie Maker to edit your composite video down to its component parts but I'd prefer to do it with VLC. There's a slight problem with that advice though in that the latest version of VLC has a well-documented problem with editing video, so I'd advise downloading and installing version 2.0.3:
http://www.oldapps.com/VLC_Player.php?old_vlc=7998
The video below explains how to extract a clip using VLC. (It's really, really easy!).
You can also take a screen snapshot using VLC, which will enable you to obtain a 'photo' but don't expect it to be of the same definition that your original images were. (To take a snapshot, simply press Shift and S together. The snapshot will then appear in your 'My Pictures' folder).
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