Play on the timeline isn't working.

A lot of my work developing involves timing audio to text and images on screen, and right now when I click the play button on the timeline it will change to the pause symbol and I'll get the Windows blue circle and then nothing happens and it returns to a play symbol. 

This is a massive file, so trying to rebuild isn't an option. I did open another file and attempt to build a slide and it's doing the same thing, so I don't think the issue is with the project file itself. 

Here is what I have tried. 

- Uninstalling, shutting down, and reinstalling the latest version

-Uninstalling the latest version, shutting down, and installing the previous version 

I know I could open a separate audio player and find my timing or cue points that way, but it will certainly take me longer and it's baffling that this was working a few days ago and just suddenly stopped working. 

HELP!!