Did you reset it already?
See https://support.mozilla.org/en-US/kb/refresh-firefox-reset-add-ons-and-settings
Kees
I really love Firefox web browser but from last few days it has become slow and hangs frequently. What is the cause? Please help me as Firefox is my favorite browser on Windows 7.
I am already made some tweaks listed in this post. But still the Firefox is slow.

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