Adding a favicon
From AbleCommerce Wiki
In order to enable favicon for you AbleCommerce store just upload the favicon.ico file to the root folder of your website.
One important thing is that IE only displays favicons in your bookmarks, which they call "Favorites" In fact, the name favicon was coined to mean "Favorites icon". As time goes on, other browsers have begun making more widespread use of favicons: in the address bar, on tabs and so on. But so far, IE only displays them after you create a bookmark. Also IE6 will display the favicon in the address bar, but only after it's been bookmarked.