Failed to browse with firefox

I have 3 browsers on my PC (Windows 7): Firefox, Internet Explorer and Google Chrome. I can't browse with Firefox.

I have 3 browsers on my PC (Windows 7): Firefox, Internet Explorer and Google Chrome. I can't browse with Firefox.
Hi!
You can resolve your problem by reinstalling the Firefox or install a new version of Firefox.
Click ctrl+alt+del and open task manager. Click on tab of” Processes”. You should see a list of task manager. Look for Firefox. Right click on it and hit “kill process tree” and then try Firefox again.
It might be caused by using antivirus Norton. Remove it from your computer. Go to control panel and click on remove programs.
Now click on Norton software and remove it . When it is completely removed from your computer, restart your computer. You would never have particular problem again.
Hello Ember!
Try to access a secure site again. If it still doesn't work, continue in the next section.
Check your proxy settings
Try to access a secure site again. Hope with these two solutions your Firefox will start working.