Your System Details list shows that the new tab page is set to about:blank.

• browser.newtab.url: about:blank

You can set the browser.newtab.url pref on the about:config page to about:newtab

You can open the about:config page via the location/address bar. You can accept the warning and click "I'll be careful" to continue.

• http://kb.mozillazine.org/about:config

See this article about the New Tab page (about:newtab):

• https://support.mozilla.org/kb/new-tab-page-show-hide-and-customize-top-sites

hello, the first issue is you're having a user.js file in your profile that might be used to override your preferences, try the following to address that: go to the firefox menu ≡ > help ? > troubleshooting information, click on profile folder/show folder and close all firefox windows afterwards. a windows explorer window should open up - in there delete the file named user.js.

secondly, install the search reset addon, which will reset the new tab page back to the default: https://addons.mozilla.org/firefox/addon/searchreset/

You can open the user.js file in a text editor via the right-click context menu and Open with (do not double-click) or in Firefox to check its content to see what prefs are set via the file and possibly reset those prefs on the about:config page or delete the prefs.js file as well to reset all prefs.

• http://kb.mozillazine.org/Preferences_not_saved