The first thing to do: make a new Windows account and try there. Firefox starts in default configuration (about: config) and no add-ons. Does that make a difference?
I have been using Firefox as my web browser since many years, and still think it is the best one for me. But in past few weeks it has given me a kind of experience that is worse than Internet Explorer!
I was using the last version before 21.0 a few weeks ago:
I open Firefox. Nothing shows up. I waited for long enough, then finally a not responding window appears(almost after 15-20 minutes). Later I wait for it to respond, and finally after waiting for atleast 20 minutes more a dialog box appears for with stop scrip option. I try to click it, but it again becomes not responding. Then I used the task manager to kill it. Restarted my PC, tried again and same thing happened. Then I uninstalled it keeping the old data. Re-installed and had the same problem within 2 days. Repeated the same procedure and then uninstalled it and removed all the old firefox data. Reinstalled and same thing happened.
Later, Firefox 21.0 was released and I updated to it. Within a week I had same problems with that too.
I have removed all the addons already so I don't know what the problem is. Please help me, since I don't wish to lose my vital bookmarks, etc.
I use Firefox Synx, if that could be a problem. Apart from that the only extensions/addons on my firefox include JAVA, .NET, and IDM