My Add-ons were disabled because my computer went into safe mode. How do I reastablish them?

Hmm, Firefox has a Troubleshoot Mode that used to be called Safe Mode. To restart Firefox normally, just close Firefox and start it up again, making sure not to hold down the Shift key.

I don't know about Windows Safe Mode affecting Firefox add-ons. Could that be a new feature? Generally speaking, Safe Mode isn't recommended for web use, so you might want to restart Windows normally.