The new update makes it impossible for me to connect to any website

Question

The update to Firefox 35 was made automatically when I opened the browser and now not a single website can appear. The browser says it can't connect to the website and that the "waiting delay is over". Usually I get this page when my Internet is off, but it's not, because I tried the same websites with two other browsers and it works perfectly. I want to use Firefox and not the other browsers, but now I'm stuck using the other ones because of that update. I'm on Windows 7 64 bit. I want to give you the troubleshooting information but I just can't because it's a Mozilla-only addon and I can't access Firefox as I just said.
There is an image of the error message (in French) but you get what it means.

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}