Sometimes, 'not responding' means the computers CPU is overworked.

Start Firefox in Safe Mode {web link} by holding down the <Shift> (Mac=Options) key, and then starting Firefox.

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

https://support.mozilla.org/kb/Firefox+is+already+running+but+is+not+responding

https://support.mozilla.org/en-US/kb/firefox-slow-how-make-it-faster

https://support.mozilla.org/en-US/kb/firefox-uses-too-many-cpu-resources-how-fix

https://support.mozilla.org/en-US/kb/firefox-uses-too-much-memory-ram

https://support.mozilla.org/en-US/kb/firefox-hangs-or-not-responding

If the above doesn't help, Start your Computer in safe mode with network support. Then start Firefox. Try Safe websites. Is the problem still there?

http://encyclopedia2.thefreedictionary.com/Linux+Safe+Mode Starting Any Computer In Safe Mode; Free Online Encyclopedia

not running other apps cpu is not overloaded I have tried the safe the safe mode it did not solve anything I am at the point of looking for for another browser I have been with Mozilla for ages but this is getting old.

What about the computer in safe mode?

When did the problem start? What Firefox version?

See if you can find updates for your Intel(R) HD Graphics 4600 as they are A little old : driverDate: 9-29-2016 You can Google Intel(R) HD Graphics 4600 and find the download page but you may have to know what generation chipset you are using. CPU-Z would tell you this https://www.cpuid.com/ Can also try : https://www.intel.com/content/www/us/en/support/detect.html I see a few errors in the drivers so this is possibly a reason having issues with Firefox 57. It 's new engine is CSS and it looks at pages like that then renders it as pixels. Old Video Card Drivers can cause a range of issues. Also keep up dating never know when they will stop supporting your card.

You could try this please : Go the Menu 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 turn it off. Run it later and see as you turn things back on and test it, and again. Restart Firefox after making these changes please.

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