hello, you appear to have an unwanted user.js file in your profile - please try this: go to the firefox menu ≡ > help ? > troubleshooting information > profile folder - "show folder", then a new window will open up. in this window look out for a file named user.js (it might be used to overwrite your custom settings). in case it is present , delete or rename this file and restart firefox afterwards.

How to fix preferences that won't save

Thanks - I was finally able to get rid of the Yahoo home page only by uninstalling Firefox, then going into the C program files and deleting leftover junk in Mozilla before downloading and reinstalling from the Mozilla website. (I'd tried uninstalls before, but without cleaning out the clutter afterwards, it just reset Yahoo. Very annoying!) I appreciate your time and suggestion. MM