Audio and mpg won't play in Viewer

I am running Windows 10 Home 64bit with DO 11.

I built this new rig a few months ago and Audio files like mp3 and wav and ogg will not play in the viewer.

Mp4 and mov files will not play in the Viewer. Also, some mpgs will play and other mpgs will not. But wmv, avi files will play with the default Movie Viewer Plugin.

I was not sure if I had added some plugins since I installed DO11. So I backed up the Viewer, VFSPlugins, and x86 folders, and then reinstalled DO11. When I compared the folders to the backups they were the same and it all still works the same. So, I don't know what is wrong.

Where do I start to fix this?

Enable/fix playback of various media formats in Opus -- Enable playback of MOV, MKV, FLV movies/videos, MP3 audio, etc.