Hello Luz.

I can't understand if this is an usability issue or a genuine problem you're having. So make sure you go into Tools > Options > General > Startup:When Firefox stars: > Show my windows and tabs from last time if you want Firefox to always remember your previous section. If you select something else, to make Firefox ask you whether you want to save multiple tabs on close, go into Tools > Options > Tabs and tick Warn me when closing multiple tabs.

If you're talking about restoring previously closed tabs, and it's not working at all, please go into Help > Troubleshooting Information... (alternatively, access about:support in your location bar) and click "Copy all to clipboard". Then paste here. Hopefully that will give me a bit more information to work with.

That said, it's possible that you are having a problem with some Firefox add-on that is hindering your Firefox's normal behavior. Have you tried disabling all add-ons (just to check), to see if Firefox goes back to normal?

Whenever you have a problem with Firefox, whatever it is, you should make sure it's not caused by one (or more than one) of your installed add-ons, be it an extension, a theme or a plugin. To do that easily and cleanly, run Firefox in safe mode (don't forget to select Disable all add-ons when you start safe mode). If the problem disappears, you know it's from an add-on. Disable them all in normal mode, and enable them one at a time until you find the source of the problem. See this article for information about troubleshooting extensions and themes and this one for plugins.

If you need support for one of your add-ons, you'll have to contact its author.

If the problem is not disappears when all add-ons are disabled, please tell me, so we can work from there.

Hi Morbus,

Thanks for your quick response. I set Tools>Options>General>Show my windows and tabs from last time as you told me, but it didn´t work. I also disabled add ons and ran the Safe Mode, though I still got no solution, so this is my Troubleshooting Info:

  Application Basics
        Name         Firefox
        Version         3.6.7
        Profile Directory
          Open Containing Folder
        Installed Plugins
          about:plugins
        Build Configuration
          about:buildconfig

  Extensions
        Name
        Version
        Enabled
        ID
        AboutPink         0.7         false         aboutpink@pinktheme.com
        Forecastfox l10n         0.7.2008093001         false          
        Freecorder Toolbar         2.5.6.0         false         {1392b8d2-5c05-419f-a8f6-b9f15a596612}
        Java Console         6.0.05         false          
        Noia 2.0 eXtreme OPT         3.76         false         noia2_option@kk.noia
        Personas         1.5.1         false         personas@christopher.beard
        RealPlayer Browser Record Plugin         1.0         false          
        PinkPaulaPack         2.0         false         pinkpaula-combo@pinktheme.com

  Modified Preferences
      Name
      Value
        accessibility.typeaheadfind.flashBar         0
        browser.history_expire_days         0
        browser.history_expire_days.mirror         180
        browser.places.importBookmarksHTML         false
        browser.places.importDefaults         false
        browser.places.leftPaneFolderId         -1
        browser.places.migratePostDataAnnotations         false
        browser.places.smartBookmarksVersion         2
        browser.places.updateRecentTagsUri         false
        browser.startup.homepage         http://www.google.com
        browser.startup.homepage_override.mstone         rv:1.9.2.7
        extensions.lastAppVersion         3.6.7
        network.cookie.prefsMigrated         true
        places.last_vacuum         1279077206
        print.print_bgcolor         false
        print.print_bgimages         false
        print.print_command
        print.print_downloadfonts         true
        print.print_evenpages         true
        print.print_in_color         true
        print.print_margin_bottom         0.5
        print.print_margin_left         0.5
        print.print_margin_right         0.5
        print.print_margin_top         0.5
        print.print_oddpages         true
        print.print_orientation         0
        print.print_pagedelay         500
        print.print_paper_data         0
        print.print_paper_height         11,00
        print.print_paper_size         5636352
        print.print_paper_size_type         1
        print.print_paper_size_unit         0
        print.print_paper_width         8,50
        print.print_printer
        print.print_reversed         false
        print.print_scaling         1,00
        print.print_shrink_to_fit         true
        print.print_to_file         false
        print.print_unwriteable_margin_bottom         0
        print.print_unwriteable_margin_left         0
        print.print_unwriteable_margin_right         0
        print.print_unwriteable_margin_top         0
        privacy.clearOnShutdown.cookies         false
        privacy.cpd.cookies         false
        privacy.sanitize.migrateFx3Prefs         true
        privacy.sanitize.promptOnSanitize         false
        privacy.sanitize.sanitizeOnShutdown         true
        security.warn_viewing_mixed         false

I hope you find this useful. Thanks again :)

Thank you very much for your help.