hello, this is just a temporary promotion on the firefox start-page. if it bothers you, you can set a different homepage: How to set the home page

That is not my chosen solution. It is installed on my computer and eliminates part of Norton 360.

I want this new feature to be removed from my computer

if you're having issues with norton then that's an entirely separate issue. according to norton their toolbar is compatible with firefox 22. please run the norton liveupdate repeatedly & until all components are up-to-date. in addition make sure that the toolbar is enabled under firefox > addons > extension afterwards.

for more information refer to http://community.norton.com/t5/Norton-Toolbar-Norton-Identity/Firefox-22-Support-for-Norton-Toolbar/td-p/979947

Firefox OS itself is a mobile operating system for ARM-based mobile devices and not Windows so it could not have installed. https://developer.mozilla.org/en-US/docs/Mozilla/Firefox_OS

You perhaps installed the Firefox OS Simulator extension. https://addons.mozilla.org/en-us/firefox/addon/firefox-os-simulator/

Can you attach a screenshot?

• http://en.wikipedia.org/wiki/Screenshot
• https://support.mozilla.org/kb/how-do-i-create-screenshot-my-problem

Use a compressed image type like PNG or JPG to save the screenshot.