Ok even 3 tabs open.

If not already done so please update to 57.0.2 : https://support.mozilla.org/en-US/kb/update-firefox-latest-version

Check if fix worked : Go to the Firefox 3 Bar Menu --> Help ? --> Troubleshooting Information Page and take a look in the Accessibility section if accessibility is set to "true" there. if yes, go to the Firefox 3 Bar Menu --> Options --> Privacy & Security panel and under Permissions check the setting to Prevent Accessibility Services from accessing your browser. Restart Firefox

If is there or still have issues : 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. Note: 0 = No Multi-proccesor = slow again. TRY 2 Restart Firefox after making these changes please.

If there is crashing : send bp- file as directed : https://support.mozilla.org/en-US/kb/firefox-crashes-asking-support only need last 3 if current.

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

Ok I tried all 3 things again & this one worked. Go the Menu then Tools --> Options --> Performance and untick everything. change the recommended size lower then see how it runs. Note: 0 = No Multi-proccesor = slow again. TRY 2 Restart Firefox after making these changes please. I think what I did wrong was I didn't restart firefox. I wish I knew what it meant about what I did. I have 16gb Ram.

Thanks for your help.