Hello john_m_hardin,
Thank you for reaching out to Apple Support Communities, and we'll be happy to help in any way we can. We understand you're having issues with playing content in iTunes. Follow these steps below:
Quit iTunes on your PC along with any other apps running. Restart your Windows PC.
Launch iTunes and try watching a movie: Play movies and other video in iTunes on PC. Be sure to test this out with more than one movie. (With the issue not occurring in music videos, you'll want to use movies during this troubleshooting)
If there is no change, go to your purchase history to see if you can redownload the movie. If it's listed, delete the movie from your library, and download it again: Redownload TV shows and movies that you purchased - Apple Support
If the movie will not play when downloaded, try streaming the movie also: If you can't stream or watch movies or TV shows from the Apple TV app, iTunes Store, or third-party apps.
If you're unable to stream it all, check out this article for more troubleshooting of your iTunes for Windows: Gather and use iTunes Diagnostics in iTunes for Windows
We hope this helps.
Cheers!