If they are part of Firefox's "form memory" then usually you can remove a suggestion from the part of the form where it appears by using the down arrow key to highlight the suggestion and then the Delete key to delete it.

Does that work on the form where you want to remove it?

There are extensions which allow you to see and edit ALL of the saved form autocomplete data if you want to do bulk housekeeping. For example: https://addons.mozilla.org/firefox/addon/form-history-control/

(Firefox's built-in features for cleaning form data are "all or nothing".)

Use these steps to remove saved (form) data from a drop-down list:

1. click the (empty) input field on the web page to open the drop-down list
2. highlight an entry in the drop-down list with the mouse or cursor Down key
   do not click the mouse or press the Enter key
3. press the Delete key (on Mac: Shift+Delete) to delete the highlighted entry

Note that your System Details List shows multiple Flash plugins.

1. Shockwave Flash 18.0 r0
2. Shockwave Flash 19.0 r0

You can find the installation path of all plugins on the about:plugins page.

• http://kb.mozillazine.org/Issues_related_to_plugins#Identifying_installed_plugins

You can check the Flash player installation folder for multiple Flash player plugins and remove older version(s) of the plugin (NPSWF32) and possibly (re)install the latest Flash player.

• (32 bit Windows) C:\Windows\System32\Macromed\Flash\
• (64 bit Windows) C:\Windows\SysWOW64\Macromed\Flash\