My passwordmanager disappeared

Tonight I upgraded my browser fromn Firefox 3 to 4.  When I opened Firefox, my password manager box had dissappeared.  Is there an easy way to find it?  I have looked in my norton files and its not there.  I don't want to download it again, as any new one won't have my passwords.  Thanks for your help

Tonight I upgraded my browser fromn Firefox 3 to 4.  When I opened Firefox, my password manager box had dissappeared.  Is there an easy way to find it?  I have looked in my norton files and its not there.  I don't want to download it again, as any new one won't have my passwords.  Thanks for your help