Helpful Reply

If you use ZoneAlarm Extreme Security then disable Virtualization and reinstall Firefox.
Other security software may have similar features to prevent Firefox from updating files properly.

See:

• http://kb.mozillazine.org/Browser_will_not_start_up#XULRunner_error_after_an_update

Do a clean reinstall and delete the Firefox program folder before reinstalling a fresh copy of Firefox.

• C:\Program Files\Mozilla Firefox\
• http://kb.mozillazine.org/Installation_directory

Download a fresh Firefox copy and save the file to the desktop.

• Firefox 17.0.x: http://www.mozilla.org/en-US/firefox/all.html

Uninstall your current Firefox version, if possible, to cleanup the Windows registry and settings in security software.

• Do NOT remove personal data when you uninstall your current Firefox version, because all profile folders will be removed and you will also lose your personal data like bookmarks and passwords from profiles of other Firefox versions.

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.
• http://kb.mozillazine.org/Uninstalling_Firefox

Your bookmarks and other profile data are stored in the Firefox Profile Folder and won't be affected by an uninstall and (re)install, but make sure that "remove personal data" is NOT selected when you uninstall Firefox.

• http://kb.mozillazine.org/Profile_folder_-_Firefox
• http://kb.mozillazine.org/Profile_backup

• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Clean_reinstall

Question owner

Cor-el Thanks for reply. However,I see you said DO NOT remove personal data when I uninstall current version, so I can get a fresh copy of Firefox. How do I avoid removing my personal data?

Question owner

By the way, I use VIPRE Security.

The uninstall window has a check-box to keep or remove your personal data and if that setting is selected then Firefox will remove all profile folders.
This will cause you to lose all personal data like bookmarks and stored passwords.

This problem doesn't require a new profile and deleting the Firefox program folder and a reinstall should be sufficient.

• (32 bit Windows) C:\Program Files\Mozilla Firefox\
• (64 bit Windows) C:\Program Files (x86)\Mozilla Firefox\

See my above reply about how to make a backup of your personal data as is always recommended.

Question owner

When I go to mozilla.org and search for installer, it displays several. Am i to use the one described as www.mozilla.org/projects/firefox/ue/installer ? Sorry to be so much trouble, but this is a bit confusing.

You can click the green button at the top right to download Firefox.

• http://getfirefox.com

• http://www.mozilla.org/firefox/features.html

Question owner

New question: Have downloaded a new copy of Firefox to my desktop. Cannot find screen or place to UNINSTALL. Where do I find that? If I go to Add/Remove Programs, I cannot find the place you told me to click on to avoid deleting my personal data.

Question owner

Went to Control Panel, where I should be able to get to Uninstall, from what I have read. My Control Panel screen has no PROGRAMS option, so cannot go to Programs and Features, where I understand I can find UNINSTALL. What am I missing here?

An uninstall most likely doesn't help in this case, only deleting the Firefox program folder to remove all the files to do a clean (re)install will make sure that Firefox gets installed properly.