Next to the magnifying glass button there is another button, in the shape of a small triangle, that produces a menu of search engines. If your browser is Firefox, the button glows blue when you visit noflail.com. Click on it and choose Noflail Search in the menu that appears.
If your browser is Internet Explorer 7, the button glows orange, and clicking on the button also produces a menu with an entry labeled Noflail Search. HOWEVER, do not click on that entry! (If you do, Noflail Search will be installed in the Search Box, but it will go away when you restart your browser.) Instead, roll your mouse over Add Search Providers. This produces a submenu to the side, with a single entry labeled Noflail Search. Click on THAT entry. Then on the dialog box that pops up, check the box Make this my default search provider and click the button Add Provider.
You cannot do this in Internet Explorer 6 or Safari.
Instead of putting Noflail Search in your browser's search box, or in addition to that, you may want to set it as your browser's Home Page.