Why can't my brother use Firefox anymore?

I just recently installed Windows 7 Ultimate; he could use FF before I installed the Realtek HD audio driver and some other standard stuff like CCleaner and Speccy. Now he can't use FF. Clicking the icon does nothing. Trying to run it from the task manager also does nothing. It doesn't even start. He can use other browsers though. What's the problem?

Start FireFox in the safe mode (you can do it by

going to Start->Programs->Mozilla). Disable all the

add-ons. Exit. Restart.

It should work, unless you have installed a Firewall

or Anti-Virus, which is preventing it's start-up.




Sheikh 'Foxy' Chilli

Well, if still it doesn't work uninstall it completely. Fix your registry. Reinstall it should work. By they now opera has also got extensions.

@sheikh_chilli when were you recruited by the elite police. I'm turning green with envy.

Safe mode didn't work, but he's taken a liking to Opera now. :P

But could there have been a solution besides the uninstall? Because FF works perfectly fine on my account and on my sister's account. I don't want to have to uninstall.

FF doesn't store anything important in the registry because its a cross platform application and there is no registry in OS other than Windows. What you can do is create a new profile for your brother. Most likely his current firefox profile is corrupt. See instructions for creating a new FF profile: