In order to have the ATOM search engine in your IE8' Search Box, follow the next steps:
Open Internet Explorer.
Find the "Search Box", on the top right corner. (Marked in Blue)
Click on "Find more Providers". (Marked in blue)
Scroll to the end of the page IE8 opened and click on "Create your own Search Provider". (Marked in Blue)
Copy and Paste the following URL (in Italic) on the "URL" field (Marked in Blue): http://www.google.com/cse?cx=partner-pub-6290821856012699%3Asl88gkf2wfo&ie=ISO-8859-1&q=TEST&sa=Search
Paste "Atom | Search" on the "Name" Field (Marked in Green).
Click "Install Search Engine". (Marked in Red)
Tick "Make this my default search provider", then "Add".
Finished. You now have the most sleek and smart search engine on your Browser ! Don't forget to set Atom|Search as your homepage !