I am hardly an expert user of WMM and it may not be on my work PC. If it is, I will see what I can do; if not, I will have to wait until I get to my home PC.
Watch this space.
Step 1: Open WMM.
Step 2: Under Capture Video, select Import Video (this is assuming you have video files on your computer.) Eventually the opening screen of the video will show on the right hand part of the screen with a start/stop/pause/etc. control bar. Click the start button until the part of the video you want to manipulate approaches, then click pause. The two middle buttons of the forward/backward group move you one frame backward or forward at a time. Use these to get the frame you want to save.
Step 3: Under the Tools heading at the top, select Take Picture From Preview and save the image in the folder you want to keep it. You can also use the "camera" iconned button at the extreme right instead of the tools drop down.
That should be all you need to save frames from video files. WMM does not work with all video types so if you are saving your own videos, try to save them in a format WMM accepts.
OK, now I'm starting to get the "hang" of the process and am anxious to get going on this little project. Many, many thanks to all who have offered their help on this bewildering (for an old guy) project. BLASTER (Bob in So. CO).