Force a logout of the website

Situation:  

A user has logged into a website to fill out a survey on our kiosk machine.

If the user does not log out of his/her session, and the browser resets to the home page and the user is still logged in.

Is there a way to force a logout?

We have Private Browsing enabled.

Choose the "Reset IE" option under the "IE Lockdown/Browser Options" tab.

The version we were running did not have that option.  I just installed the new one and I see it in there.  We will test it now.

That did it.  Thanks!