I just upgraded from Windows 8 to Windows 8.1

I am using a Canon FS10 camcorder with Pixela ImageMixer 3 SE for SD ver. 3.1.3.

I can move and edit still photos but when I move videos into MovieMaker all that plays is the audio.

Windows Media Player plays my stills and videos correctly but when they arrive in MovieMaker only the audio plays.

I have already tried the "uncheck the Trusted Sites and add codecs.Microsoft.com thing." Didn't fix the problem.

Also, my files show up in Control Panel as "MPEG" files.

What am I doing wrong?