Missing Video Codecs

I have several downloaded video files. Some of these will play, but most give me pop-up with this error: "No required video codecs were not found" Further down it says "Invalid video format" and "The file is damaged"

I know these files are not corrupt because they will play in another video player and through VLC. I reinstalled both the PLAY'A app and the K-lite codecs, but this has not fixed the issue. It seems that PLAY'A is not accessing the codecs. How do I get it to do so?

I am using an Oculus Rift S with Windows 10.

Thanks.