I wanted to install a new add-on to my 3.6.10 version and was advised that I needed to download an update to 3.7.0 I had Firefix open with several tabs that I was using. I downloaded the beta 4.0 and it would not install.... saying that Firefox was already running. I opened Task Manager in my Windows XP SP3 and deleted the running Firefox in 'Processes'. When I have done this before, the next time I restart Firefox, I am asked if I want to reopen the tabs as they were. This time there was no such question and I am now apparently unable to reopen the several tabs that I was working on and I have lost a great deal of valuable work. AS an idea for the future... could it be possible to save 'sets' of tabs so that when I am working on a project and skipping between web sites.. I can safe the tab set that I have so that I can reinstate it at another time? This is different from the 'Tools/General setting to reinstate the tabs when the browser is reopened... I am looking to be able to save different sets.. for instance a 'News' set so that I can open my regular News sites first thing in the morning... then get to work on a particular project by recalling another Set... later I may change projects and it would be great to be able to recall another saved 'Set'. In the meantime, I remain frustrated.!