Two ways that your settings might get switched when you exit and restart Firefox are: (1) user.js file This is an optional settings file Firefox reads at startup which preempts your previous session settings. See the following article for information on how to track down whether you have a user.js file and how to remove it: [[How to fix preferences that won't save]]. If you do not see file extensions like .js, you can turn off hiding of file extensions using the steps in this article: [http://support.microsoft.com/kb/865219]. The user.js file usually is created by external software and may return if the cause is not removed. This may require a visit to the Windows Control Panel, Uninstall a Program, or clean-up using tools such as the ones listed in this article: [[Troubleshoot Firefox issues caused by malware]]. (2) "Surfing Protection", "Home Page Protection", etc. Recently users have discovered that their security or utility software has an added feature that prevents changes to their home page setting, both unwanted and wanted. If you use Advanced SystemCare or other popular security/utility software, see whether it has this feature and turn it off so your changes do not get reverted.