For over a week I've not been able to open FF--I get a message that says "FF is already running but is not responding. To open a new window, you must first close the existing FF process, or restart your system." I've tried the following: scanning my computer completely for malware and viruses (got rid of all threats); going into Task Manager and looking for multiple versions of the mozilla.exe or firefox.exe (in fact there were none at all listed); downloading various versions of FF (3, 4, and 5). None of this has made a difference. I've been using Google Chrome for some time, as a result. But all my bookmarks are in FF, and they're very necessary for my work. I also like FF.