Disable XP / IE Password Saves

Hello,
I am a newbie here and would GREATLY appreciate your assistance. I am an IT Tech with a small (25 machines) sub-organization. We are on a domain and are required to enter usernames and passwords to login to our domain (thru Windows Logon). I would like to know if there is a method to disable the ability to save passwords within websites for ALL users of a computer without having to make those changes while that user is logged in. Logged in as administrator, I have unchecked the “Save Passwords” box as an option in XP, but that doesn’t seem to affect the other user accounts on that system. Thanks!!
-Allen