This problem exists domain-wide for all users. Affects all IE7 and IE8, XP and 2K3. Enhanced security turned off on 2K3. Administrators are unable to add sites as well as limited users. I can click on Sites button, but add sites window is grayed out. There is no known group policy that has intentionally changed or restricted trusted sites. HKeyCurrentUser\...\Zones\2 = 47 (71)
I have created a test GP to which I have set filtering to myself only and imported current security zones and settings, but nothing changed. Any ideas?