Certain Firefox problems can be solved by performing a Clean reinstall. This means you remove Firefox program files and then reinstall Firefox. Please follow these steps:

Note: You might want to print these steps or view them in another browser.

1. Download the latest Desktop version of Firefox from mozilla.org (or choose the download for your operating system and language from this page) and save the setup file to your computer.
2. After the download finishes, close all Firefox windows (or open the Firefox menu and click the close button ).
3. Delete the Firefox installation folder, which is located in one of these locations, by default:
   • Windows:
     • C:\Program Files\Mozilla Firefox
     • C:\Program Files (x86)\Mozilla Firefox
4. Now, go ahead and reinstall Firefox:
   1. Double-click the downloaded installation file and go through the steps of the installation wizard.
   2. Once the wizard is finished, choose to directly open Firefox after clicking the Finish button.

More information about reinstalling Firefox can be found here.

WARNING: Do not use a third party uninstaller as part of this process. Doing so could permanently delete your Firefox profile data, including but not limited to, extensions, cache, cookies, bookmarks, personal settings and saved passwords. These cannot be easily recovered unless they have been backed up to an external device! See Back up and restore information in Firefox profiles.

Please report back to say if this helped you!

Thank you.

nope. same problem again.

See:

• https://support.mozilla.org/kb/how-run-firefox-when-your-profile-missing-or-inacc

This is usually caused by a problem with the profiles.ini file and the profile marked as Default=1 in this file is no longer present on the hard drive.

• Windows: %AppData%\Mozilla\Firefox\
  C:\Users\<user>\AppData\Roaming\Mozilla\Firefox\Profiles\<profile>\
• Linux: ~/.mozilla/firefox/
• Mac: ~/Library/Application Support/Firefox/

You can use one of these to make Firefox create a new default profile or reuse an existing profile:

• Delete the profiles.ini file to force Firefox to create a new default profile
• Use the Profile Manager to create a new profile
  Use "Choose Folder" when you create a new profile to select the location of a lost profile and recover this profile

• http://kb.mozillazine.org/Profile_Manager
• https://support.mozilla.org/kb/Managing+profiles
• http://kb.mozillazine.org/Profile_folder_-_Firefox

I can't find the .ini file.

Did you look in this location?

• C:\Users\<user>\AppData\Roaming\Mozilla\Firefox\Profiles\

The "AppData" folder in Windows Vista and later Window 7+ versions and the "Application Data" folder in XP/Win2K are hidden folders.

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

Windows hides some file extensions by default. Among them are .html and .ini and .js and .txt, so you may only see file name without file extension. You can see the real file type (file extension) in the properties of the file via the right-click context menu in Windows Explorer.

Well it wasn't there, it was in another folder. I found it and it seems that it's working.

Thanks for your help.