How to Restore Internet Explorer as the Default Browser
Installing and using different web applications could change your default Internet browser. If you have other browsers installed on your computer or you recently uninstalled them, your computer may prompt you to select a default browser. However, if your computer does not prompt you to choose a default application and you would like to set Internet Explorer as your primary web browser, you can do so easily within the application itself. Checking the "Tell me if Internet Explorer is not the default browser" check box under the "Programs" tab allows Internet Explorer to monitor your default browser selection.
Launch Internet Explorer (IE), click "Tools" and then choose "Internet Options."
Select the "Programs" tab and then choose the "Make default" button.
Apply the changes by clicking "OK" and then closing Internet Explorer. You have successfully set Internet Explorer as the default web browser.