a Firefox refresh wouldn't change your DVD drives being able to read DVD's, however, updating to windows 10 will.

http://answers.microsoft.com/en-us/insider/forum/insider_apps-insider_video/windows-10-tp-wont-play-dvds/1f1f1a07-23d2-4484-b891-0e30cc3a0b8c?auth=1

As suggested in that forum, I'd install the free, open-source VLC player, which will enable you to watch DVD's for free.

I already have the VLC player, and discs didn't show up there either. Both drives have been working since the day I installed Windows 10 when it was initially available, so that wasn't the problem. The only thing that changed was the Refresh of Firefox. That refresh also changed other things that I needed to set up again. I did solve the problem, however, by uninstalling the drives and letting Windows re-install them