Thanks guys... I also got an answer from a support ticket, and it's simple, easy, and it worked:

• Make sure poser isn't running.
• Open a file explorer window and enter this in to the folder location bar:
• %appdata%\Poser\13\PythonScripts\
• Look for a file named mainButtons.json
• Move or delete that file.
• Relaunch Poser and the factory python buttons will be restored.