@OracleLunaFaye I never record but tested this, and got video files that would not open in Windows Media Player nor in Windows Video Editor when I had Capture Quality set to Uncompressed; about a third would not open, as opposed to all when set on High.
Could you check and possibly change your settings:
Game Options>Screen Capture>Capture Quality: High (not Uncompressed)
If that doesn't help and you want to keep troubleshoot, please take a screenshot of your settings in Screen Capture; as well as Graphics, and attach them to your post.
If you get an error message when trying to open the files please write/screenshoot it too.
Other things you could try:
Try to open the, possibly, uncompressed files in a different video editor suitable for it. I don't record, so don't know of any really, but you could search on: Power Director and Wondershare Video Editor etc.
Use an external recording program instead of the in-game recording function. Again, no personal experience, but some players recommend OBS, Open Broadcast Software; since it is free and possible to change the settings to relieve your CPU if needed. Tutorial here, follow the link on it for the actual program: