You might have Permanent Private Browsing mode checkmarked in Tools | Options | Privacy although that wouldn't influence the way Bookmarks will behave.

I checked your system details, but can't see Java anywhere? Firefox won't work properly without it. If it is installed, you should be able to see in by going to Tools | Add-ons | Plugins. It looks like the settings you see in the screenshot.

If you don't see it there, go to http://www.java.com/en/ and install it.

Also, please go to the Plugins Check page and update where necessary.

If the above troubleshooting steps don't fix the problem, try running Firefox in Diagnose Firefox issues using Troubleshoot Mode. If it functions properly in that configuration, then one of your add-ons is the culprit.

This can also be caused by a problem with the file places.sqlite that stores the bookmarks and the history.

• http://kb.mozillazine.org/Bookmarks_history_and_toolbar_buttons_not_working_-_Firefox