There are several possible causes for that error message, for details see "Firefox is already running but is not responding" error - How to fix.

I have gone to the link that you supplied . In the task manager-- ending the entry for Firefox.exec did not resolve the problem. I located my profile in the start menu In the run tab And entered %APPDATA%\Mozilla\Firefox\Profiles\as instructed. I received a cannot delete parent file is corrupted or unreadable. I then ran the Chkdsk (check disk )and tried the process again with no improvement . I have uninstalled Firefox, and redownloaded It. Still no improvement. I want my Firefox WHAAAAAAA

If you are getting an error message from Windows about not being able to delete a file, there are some utilities that may help. See http://www.thefreecountry.com/utilities/deletelockedfiles.shtml

Create a new profile as a test to check if your current profile is causing the problems

See Basic Troubleshooting: Make a new profile

If that new profile works then you can transfer some files from the old profile to that new profile (be careful not to copy corrupted files)

See http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Current profile was causing the problem I've opened a new one and now I am able to enter firefox. I am somewhat lost on how to retrieve my old profile and put it on my new profile help

After scratching my head I figured out how to copy the files that weren't corrupted and move them as a block to my User profile . I hovered over the first file /shift /to the last file . Right click /copy , up one folder to the parent folder which held both profiles . Hovered over the new profile and clicked paste . Prompts said replace existing files I clicked yes to all until it stopped at a corrupted file and prompted me that that file was corrupted . I went back and blocked everything from the first to the file before the corrupted one pasted them in the new profile . I repeated this process until all of the corrupted files were bypassed and all of the usable files were transferred to my new profile .

Thank you for all your help , I was losing what hair I had left scratching my head trying to figure out how to fix this (on the upside my butt enjoyed a vacation)

After a few hours of checking my profile, copying profiles.ini, editing profiles.ini, backing up my profile folder, etc., etc., etc. I found a very simple but effective solution. I completely uninstalled Firefox . Only this time when the Firefox uninstall dialog box popped up I checked the option "Remove my Firefox personal data and customizations". I then completely shut down and restarted. Then reinstalled Firefox, and thereby creating an entirely new profile from scratch.

The upside again was a simple and effective solution. The down side is I have had to recreate my Favorites, reinstall my add-ons, etc., but overall I am happily up and running seamlessly with Firefox again.