Firefox cannot (or refuses to) connect to any website, but connecting to local addresses (10.0.x.x) works fine.
After loading Firefox, attempting to access any website via History, bookmarks, or typed into the address bar does not result in any action whatsoever, apart from a message on the status bar flashing so briefly I can't make it out - (the status bar does report "Looking up host.." but after that, I don't see what happens until it happily reports Done. - done *what*, Firefox?)
ప్రత్యుత్తరాలన్నీ (3)
A possible cause is security software (firewall,anti-virus) that 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:
I have no such software installed on the computer in question.
Also, I doubt the issue is firewall related as other browsers (such as Safari, which I am forced to use currently) are unaffected.