You only get the Firefox profile manager if all Firefox processes are ended.

See:

• http://kb.mozillazine.org/Profile_Manager
• http://kb.mozillazine.org/Kill_application

I think I did end all Firefox processes. I restarted the computer, which required using Task Manager to stop Firefox, and then did not start Firefox after restarting the computer. If there's something else I need to do to end all Firefox processes, I'd be happy to try it.

My bottom line is that I will just use IE rather than spend inordinate amounts of time trying to fix Firefox.

As a last resort you can do a clean reinstall of the Firefox program and remove the Firefox program folder before installing a freshly downloaded full Firefox version.
Deleting the Firefox program folder should ensure that there are no problems with files that are in use by other software.

Your bookmarks and other profile data are stored elsewhere (not in the Firefox program folder) and won't be affected by a reinstall, but make sure that you do

cor-el, what is involved in a "clean reinstall"? I have already used the remove software process of XP to remove Firefox and then downloaded a clean copy, but that didn't work. Is there something more I need to do? Thanks for the help.

Just did a little research and it seems a clean reinstall involves removing my user profile. But the problem is that I can't find my profile, despite following the instructions for getting it on XP.

It is not always necessary to create a new profile.
Easiest is to use: Help > Troubleshooting Information > Profile Directory > Open Containing folder

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of your add-ons is causing your problem (switch to the DEFAULT theme: Tools > Add-ons > Themes).

See Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems and Troubleshoot issues with plugins like Flash or Java to fix common Firefox problems

If it happens after an update then a possible cause is security software (firewall) that blocks or restricts Firefox without informing you about that, possibly after detecting changes (update) to the Firefox program.

Remove all rules for Firefox from the permissions list in the firewall and let your firewall ask again for permission to get full unrestricted access to internet for Firefox.

See Server Not Found - Troubleshoot connection problems and Configure firewalls so that Firefox can access the Internet and http://kb.mozillazine.org/Firewalls

thanks. I'll try these tomorrow.

I checked and updated the plugins. I cannot start Firefox in safe mode. When I follow the instructions and click on Firefox safe mode from the start menu, nothing happens. I have uninstalled Firefox and removed my personal info and reinstalled but still the same result--Firefox apparently is running but it will not come up on my monitor. So I can't do the basic troubleshooting recommended in one of the links because I can't get to Firefox.

I appreciate your help, cor-el, but nothing seems to work and I am getting tired of trying to fix this problem.

Mozilla, are you out there?

I had the same problem on my Mac. I trashed the Firefox I had in my applications and reinstalled, but no luck. Then I trashed the new one, plus all folders that said Firefox, and reinstalled. IT WORKED! However, I've lost all of my bookmarks :(

Is there any way I can get my bookmarks back? I went to the trash and pulled out anything that said 'bookmarks' on it, but don't know what to do. I can't open them.

You can copy places.sqlite to the new profile that has been created or restore the bookmarks from the most recent JSON backup.

See:

• Recovering important data from an old profile
• http://kb.mozillazine.org/Backing_up_and_restoring_bookmarks_-_Firefox

Help > Troubleshooting Information > Profile Directory > Open Containing folder

Thank you, cor-el, I was able to get my bookmarks back! I went to the link you mentioned and followed the steps. I went to Bookmarks>Organize Bookmarks> Restore, and chose the most recent file in the 'bookmarksbackups' file that I had retrieved from the trash. All of my bookmarks were restored.

Thank you!

I'm back. Thought I would try what emily suggested. So I uninstalled Firefox again, searched for file/folders with firefox in them, deleted them, emptied the recycle bin, restarted the computer, reinstalled firefox and--got the same result. Firefox apparently gets installed and starts but it doesn't show up on my monitor. I say it apparently starts because when I shut the computer down, I get the box saying firefox has to be ended. Really don't understand what has happened.

Could your firewall settings be the problem?

http://kb.mozillazine.org/Firewalls

emily - i also have a mac, how did you uninstall firefox?..gbm

Sorry, I haven't come here lately since my problem was resolved. All I did was drag all of Firefox to the trash.