Uninstalling Firefox
This article contains instructions to uninstall Firefox and remove it from your system. Make sure you complete the last step, removing the user profile data, if you wish to completely remove Firefox or perform a clean reinstall.
Note: You should set another default browser if you are not going to reinstall Firefox and it is currently the default. You can use the information in this article as a general guide.
On Mac OS X
Drag the Firefox application to the Trash.
On Linux
Remove the firefox Installation directory, usually: /usr/lib/firefox-<version>. For example, if using Firefox 1.0 it would be: /usr/lib/firefox-1.0
On Windows
- Open the Windows Control Panel and double-click Add/Remove Programs. Select Mozilla Firefox (<version>) in the list and click “Remove” to run the uninstaller. Even if this first step fails, as it may in some cases, continue on with the rest of the uninstall instructions.
- Delete the Firefox Installation directory, located here, by default: C:\Program files\Mozilla Firefox
- If you installed the Quality Feedback Agent component (aka Talkback), open the %APPDATA%\Talkback\MozillaOrg\ folder and delete all “Firefox<somenumber>” folders found, for example, “Firefox10″ “Firefox15″ and “Firefox2″.
- Firefox 1.5 and later: Delete the “Firefox” folder containing the profile “cache” folder and “XUL.mfl” file located here: C:\Documents and Settings\Windows login username\Local Settings\Application Data\Mozilla\Firefox. On Windows 2000 and later the “Local Settings” folder is hidden by default.
- If necessary, remove the “Mozilla Firefox” shortcuts in the Windows Start -> Programs menu by right-clicking and deleting the entries. (This step should not be needed unless the Add/Remove Programs uninstaller in the first step failed.)
The Firefox uninstall will leave behind some Windows registry entries, which can be cleaned up using Windows regedit or a 3rd party registry cleaner. Note: registry editing is a potentially hazardous undertaking!.
You may also need to manually change some file associations or icons in your Windows “Folder Options -> File Types” even after setting a new default browser
Removing user profile data
This step is recommended for users who are uninstalling Firefox in preparation for a “clean reinstall”.
This will remove the Firefox user profile data, which includes bookmarks, passwords, cookies, preference settings and added extensions. Back up your profile data so that you can restore it later, if you wish, then delete the entire Firefox folder (which will include the “Profiles” subfolder and the files “profiles.ini” and “pluginreg.dat”) from the default Firefox profile path. Note that, in Windows 2000 and later, you can use “Start -> Run -> (type in) %APPDATA% -> OK” to open the hidden Application Data or AppData folder,
Source: http://kb.mozillazine.org/Uninstalling_Firefox