when I open Firefox I get an alert about an unauthorized program "updater.exe". I allow it and then a second window opens up saying "it is strongly recommended that you apply this update for Firefox as soon as possible", but it does not say what the update is. There is a link to view more information about this update, but it does nothing when I click on it.
Do not remove personal data when you uninstall the current version.
Remove the Firefox program folder before installing that newly downloaded copy of the Firefox installer.
It is important to delete the Firefox program folder to remove all the files and make sure that there are no problems with files that were leftover after uninstalling.
Your bookmarks and other profile data are stored elsewhere in the Firefox Profile Folder and won't be affected by a reinstall, but make sure that you do not select to remove personal data if you uninstall Firefox.