In screenshot 2, click the arrow on the left and show it to us. [https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode Start Firefox using Troubleshoot(Safe) Mode] {web link} A small dialog should appear. Click '''Start In Troubleshoot(Safe) Mode''' (not Refresh). Is the problem still there? 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 https://support.mozilla.org/en-US/kb/firefox-takes-long-time-start-up https://support.mozilla.org/en-US/kb/quick-fixes-if-your-firefox-slows-down https://support.mozilla.org/en-US/kb/firefox-uses-too-much-memory-or-cpu-resources MemTest Could you please run a tool from http://memtest.org/ in order to check the integrity of your RAM? You will need a thumb or disk drive to install it on. Do you let Windows handle the page file or did you set a fixed size ? Control Panel -> System -> Advanced -> Performance -> Settings If you use a fixed size for the page file then try the former and let Windows handle the page file. [https://docs.microsoft.com/en-us/windows/client-management/determine-appropriate-page-file-size#:~:text=Support%20for%20system%20crash%20dumps%20%20%20,on%20kernel%20virtual%20memory%20usage.%20%20...%20 How to determine the appropriate page file size for 64-bit versions of Windows] {web link}