Since the security alert notifying users if a particular site is secure can become cumbersome, it is tempting to disable the alert by clicking the "do not show this warning" checkbox. However, users will not know if a site is secure.
To re-enable the site security alert, go to Start>Control Panel>Internet
Options>Advanced> and click the "Warn if changing between secure and non secure mode
checkbox." You can also open Internet Explorer, click Tools>Internet Options>Advanced and
then click the secure mode checkbox.
This was first published in March 2006