first , right click on the taskbar , start task manager . then in the task manager , select , process tab . you will find firefox 32.exe or something like that . right click on that , from the pop up menu select , end process tree .do this for every firefox.exe remaining in the task manager . after ending every firefox process , now start your firefox , i hope , it will start now :)

yes, I already tried that.

I guess I will have to stop using Firefox.

It is possible that your security software (firewall, anti-virus) blocks or restricts Firefox or the plugin-container process without informing you, possibly after detecting changes (update) to the Firefox program.

Remove all rules for Firefox and the plugin-container from the permissions list in the firewall and let your firewall ask again for permission to get full, unrestricted, access to internet for Firefox and the plugin-container process and the updater process.

See:

• https://support.mozilla.org/kb/Server+not+found
• https://support.mozilla.org/kb/Firewalls

• https://support.mozilla.org/kb/fix-problems-connecting-websites-after-updating

Can you start Firefox in Safe Mode by holding down the Shift/Options key?

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

I added C:\Program Files (x86)\Mozilla Firefox to MSE excluded files and locations, then I could open FF in safe mode using the Shift key. (what is the Shift/Options key?) ... then I reset ff