Since updating to Firefox 35 it's the only browser that shows error "Unable to connect" and nothing works from the support answers to solve it

Question

so far i tried:
1. to set the windows firewall settings
2. I've reinstalled firefox
3.

Answer 1

Type '''about:preferences#advanced'''<Enter> in the address bar.
Under '''Advanced,''' Select '''Network.'''
Look for '''Configure How Firefox Connects''' and press the '''Settings''' button.
Check the settings.
Some problems occurs when your Internet security program was set
to trust the previous version of Firefox, but no longer recognizes your
updated version as trusted. Now how to fix the problem: To allow
Firefox to connect to the Internet again;
* Make sure your Internet security software is up-to-date (i.e. you are running the latest version).
* Remove Firefox from your program's list of trusted or recognized programs. For detailed instructions, see
'''[https://support.mozilla.org/en-US/kb/configure-firewalls-so-firefox-can-access-internet Configure firewalls so that Firefox can access the Internet.]''' {web link}