How to solve the error message in Firefox::"Firefox is already running but is not responding"

Firefox use only one profile at a time . It is made possible by putting a lock file in your profile folder when it starts and as soon as you exit Firefox the file is removed, if the lock file already exists when you open firefox then it shows the error message " Firefox is already running but is not responding" and a box is shown like that


It is required to close the existing firefox or restart the system.But this problem can be solved as follows.I found it from the Firefox websie and think that it should be fruitful for those who are new to the Firefox.There are different methods to overcome this error message for windos vista and windows XP .

Windows Vista : If you are receiving the above error message while attempting to start Firefox, try to restart the program. If the problem persists, do the following:

1. Restart your computer.
2. Select the Start Menu in the Windows Taskbar.
3. In the Search box, enter the following:
   %APPDATA%
4. Press Enter.
5. From the Application Data folder, navigate to Local\VirtualStore\Program Files\Mozilla Firefox.
6. Delete the file xpicleanup.dat.
7. Restart Firefox.

Windows XP :

1. Click on the Start button and select Search to open the Search Results window.
2. On the left side of the Search Results window, click on the All files and folders link.
3. Click to expand the More advanced options list.
4. Put a check mark next to Search system folders, Search hidden files and folders, and Search subfolders.
5. In the All or part of the file name field, type xpicleanup.dat.
6. Click Search to begin the search.
7. If any results are returned, delete them.
8. Restart Firefox.