Comment 3 for bug 274977

I'm also having the same problem. I ran update manager which included the firefox update. I was running firefox while the updates were installing. After the update succeeded, Firefox began to act strangly (not opening web pages, search bar didn't work), so I restarted Firefox and it wouldn't start up. When I try to launch it now, it displays "Starting Firefox..." in the bottom panel of Gnome, but after a few seconds it dissapears, and Firefox doesn't launch. I'm not that proficient with linux (which is why I use Ubuntu I suppose), but this is really critical issue for me. I've had to switch to Opera for the time being. I tried "sudo apt-get remove firefox" and then "sudo apt-get install firefox," but it didn't correct the problem.