Hi,
To uninstall FireFox completely, I suggest you restart the machine in Safe Mode and please refer to the following article:
Uninstalling Firefox
Note: The third-party product discussed here is manufactured by a company that is independent of Microsoft. We make no warranty, implied or otherwise, regarding this
product's performance or reliability.
Meanwhile, please switch to Processes tab in Task Manager and kill the FireFox process to check the result.
Thanks,
Novak
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