Most versions of Windows come with Windows Movie Maker, which is perfectly good enough for your needs.
If you've not got it, the latest version (now called 'Windows Live Movie Maker 2011') is available as a free download from Microsoft:
http://explore.live.c...-movie-maker?os=other
Once you've got your finished video, you'll want to play it. There are two video players which are both about a zillion times better than Windows Media Player. They're VLC
http://www.videolan.org/vlc/
and GOM
http://www.gomlab.com/eng/GMP_download.html
Unlike WMP, both of those players allow you to take 'snapshots' from your videos. (Don't expect superb quality though; you won't get it. That's not a fault of the programs. It's simply that there's not enough data within any video file to get really 'crisp' snapshots).
Chris