If I logout of my administrator account, login as a less privileged user and then press the back button I can access all therestricted administrator pages I was looking at with the administrator account - if I close the browser and reopen, there's no problem. So I need to do something like delete cookies from the first login, or make the sessioin expire between logins or something...help please!

this is the reason for "Press logout and close this browser"!

You can't acess to the user computer in order to delete his cookies or his "temporary internet files"

You can do a new redirect page when user press log-out saying:

"Thanks for your visit... I should close this browser window to have a sucessefully log-out"