I was using Mozilla Firefox 11 in my computer and recently I have upgraded my browser with Mozilla Firefox 12. I have windows 7 operating system in my computer. After upgrading Mozilla Firefox it has started giving me problem. Now whenever I try open bookmarks Mozilla Firefox at that time nothing happens and when I restart Mozilla Firefox and try to open at that time it works fine. I have also tried to open bookmarks from bookmarks bar but that does not make any difference. If you have any solution regarding this then let me know.