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Won't open

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Won't open says please close already running firefox or restart computer. And I have restarted and shut down and it still won't open. WHAT THE HELL I've even deleted the program and downloaded it and it just won't work. HELP!!

Won't open says please close already running firefox or restart computer. And I have restarted and shut down and it still won't open. WHAT THE HELL I've even deleted the program and downloaded it and it just won't work. HELP!!

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The application may have shut down abnormally, leaving the lock in place. To fix this, open the profile folder and delete the parent.lock file.

The quickest way to get to your profile is through Help>Troubleshooting information.. (or type about:support into the location bar) then use "Open containing folder".