I am sry for changing the status. I was not knowing what it is. I searched and found this as partial solution. use command sudo aptitude reinstall firefox-3.5
this helped to reduce the problem. Now I am getting following error message: (firefox:18250): GLib-WARNING **: g_set_prgname() called multiple times if there is any solution, please let me know. -- Gdk-WARNING **: XID collision, trouble ahead https://bugs.launchpad.net/bugs/401823 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs