Hmmm, not familiar with an icon. Can you check your disabled extensions to find the name of it?

orange Firefox button or Tools menu > Add-ons

On the left side, click Extensions, then look for the one that pulls in your IE Favorites. Is it still enabled or is it disabled? If it's enabled, then the icon might just not be in the correct location. You could try the Customize feature to move it where you want it. See: How do I customize the toolbars? | How to | Firefox Help.

If it is disable because it hasn't been updated for Firefox 5, maybe you can use the add-on named PlainOldFavorites instead.

It sounds like you had the bookmarks saved as an html file on your desktop. follow this tutorial, it will show you with pictures how to export your bookmarks again. Once you export them, just keep that file on your desktop and when you click on it it should do what you're looking for.

Saving your bookmarks to an HTML file

Do you mean like the following add-on. It adds a "Favorites" button, but leaves your IE bookmarks and does not add them to Firefox.

• https://addons.mozilla.org/en-US/firefox/addon/plainoldfavorites/

Look in your extensions (Add-ons > Extensions) to see if the one you used is there but is shown as "Disabled" or "Not Compatible with Firefox 5", then look it up by name on the following link to see if the developer updated it for Firefox 5 compatibility.

• https://addons.mozilla.org/en-US/firefox/

from internet explorer
Maybe that was a bookmarks folder that was sitting on the Bookmarks Toolbar?

Maybe you hid the Bookmarks Toolbar?

orange Firefox button > Options = is the Bookmarks Toolbar menu item check-marked? If not, click on that menu item.