This the best way to uninstall Firefox. Then Delete the Mozilla Firefox Folders in C:\Program Files and C:\Program Files(x86) Then restart system. Then run Windows Disk Cleanup. Then run it again and click the button that says Cleanup System Files. Note: your Firefox Profile is saved.

If want it all gone then delete your profile folder also : https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data Then Search some more for folders.

Change all things to read a Mac ( I have no idea about a mac)

Reinstall with Current Release Firefox 57.0 with a Full Version Installer https://www.mozilla.org/firefox/all/

• It may as if you want to refresh, say no and tell me what happens please.*

On reinstall :

Then Tools --> Options --> Performance and untick everything. change the recommended size lower then see how it runs. Hardware Acceleration might have also been a issue so run it and see and turn things back on and test it.

Going back : unfortunately 56.0.2 is no longer safe to use for every day use, but 52.5.0 ESR is! It will continue to get security updates until May 2018, and you can download and install it from this page: https://www.mozilla.org/en-US/firefox/organizations/all/

Please update your Video Card Drivers. Most issues are caused by old outdated and corrupted drivers.

Please let us know if this solved your issue or if need further assistance.

Pkshadow said

This the best way to uninstall Firefox. Then Delete the Mozilla Firefox Folders in C:\Program Files and C:\Program Files(x86) Then restart system. Then run Windows Disk Cleanup. Then run it again and click the button that says Cleanup System Files. Note: your Firefox Profile is saved. If want it all gone then delete your profile folder also : https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data Then Search some more for folders. Change all things to read a Mac ( I have no idea about a mac) Reinstall with Current Release Firefox 57.0 with a Full Version Installer https://www.mozilla.org/firefox/all/

• It may as if you want to refresh, say no and tell me what happens please.*

On reinstall : Then Tools --> Options --> Performance and untick everything. change the recommended size lower then see how it runs. Hardware Acceleration might have also been a issue so run it and see and turn things back on and test it. Going back : unfortunately 56.0.2 is no longer safe to use for every day use, but 52.5.0 ESR is! It will continue to get security updates until May 2018, and you can download and install it from this page: https://www.mozilla.org/en-US/firefox/organizations/all/ Please update your Video Card Drivers. Most issues are caused by old outdated and corrupted drivers. Please let us know if this solved your issue or if need further assistance.

Thanks for the help ^_^ It actually worked

How I found the folder: Before deleting Firefox itself, I clicked the menu button then went to Help, then Troubleshooting Information. Afterwards I clicked the 'Show in Finder' button by the part that says Profile Folder. It should show open you a folder with the name 'Profiles' at the top. Right click it then click 'Application Support', find 'Firefox' and delete it. Then, you can go and delete the app itself and re-install everything.

I didn't do the ticking options part or the Windows Desk Cleanup. Either way, I checked and everything was reset already. No history, no add-ons, just factory settings

I am currently using OS X Mavericks, but hopefully this works for Yosemite users and above.