No one? just to add up some info, I can open it when I first boot my PC, but after a while it stops opening pages and in settings I get "Restart to update Nightly" message. When I click it, then I get the above mentioned problem. Same happens when I close the browser myself and try to start it again.

Let’s do a full clean re-install; [http://www.mozilla.org/en-US/firefox/all/ Download Firefox For All languages And Systems] {web link} Beta, Developer, Nightly versions https://www.mozilla.org/en-US/firefox/channel/desktop/ Save the file. Then '''Close Firefox. ''' Using your file browser, open the '''Programs Folder''' on your computer. '''Windows: ''' C:\Program Files C:\Program Files (x86) '''Note:''' Check Both Folders '''Mac: ''' Open the ''' "Applications" ''' folder. https://support.mozilla.org/en-US/kb/how-download-and-install-firefox-mac '''Linux: ''' Check your user manual. If you installed Firefox with the distro-based package manager, you should use the same way to uninstall it. See Install Firefox on Linux; https://support.mozilla.org/en-US/kb/install-firefox-linux If you downloaded and installed the binary package from the Firefox download page, simply remove the folder Firefox in your home directory. http://www.mozilla.org/firefox#desktop ++++++++++++++++++++++++++++ Look for, and remove any '''Mozilla''' or '''Firefox''' program folders. Do not remove the '''Mozilla Thunderbird''' folder if there is one. '''Do Not''' remove any profile folders. After rebooting the computer, run a registry scanner if you have one. Then run the installer. +++++++++++++++++++++++++++ If there is a problem, start your '''Computer''' in safe mode and try again. http://encyclopedia2.thefreedictionary.com/Linux+Safe+Mode This shows how to Start all Computers in Safe Mode; Free Online Encyclopedia