Music videos not playing on iTunes

I'm having issues with music videos not wanting to play on iTunes be it the ones I've purchased or the ones I want to preview. I've run a diagnostic check on iTunes and made sure I've got the most recent version of iTunes and I still get an error message saying Video playback is not supported on this computer even though I've never had an issue with doing so until recently.Does anyone have an idea what in the world is going on now with iTunes that this new issue has all of the sudden appeared?