IE Content Advisor wont disable

The following steps will remove any password set in the Content Advisor and allow you to reset the program to its original state.

1) Click on Start and choose Run.
2) Type in Regedit and select OK.
3) Now click on the little plus sign to the left of HKEY_LOCAL_MACHINE.
4) Continue to drill down, always clicking on the plus sign at the left of the named key, through Software, Microsoft, Windows, Current Version and Policies.
5) Now click on the Ratings folder.
6) In the right pane of the Regedit window, you'll see an icon called Key. Click on it and press Delete.
7) Next, choose Registry and then Exit to exit Regedit. You've just deleted your original Content Advisor password.
8) Restart the computer and run Internet Explorer again.
9) Choose View and then Internet Options (or Options for version 3.x)
10) Click on the Content tab and click on Disable. When asked for a password, don't enter anything; just click on OK. This will disable Content Advisor because there's no longer a password.

Click Start,Run,type in Regedit

Navigate to

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Policies\Ratings

Delete the entry in right-pane KEY

Reboot

Start IE,go to the Tools Menu,select Internet Options

Select the Content tab,click on Disable,when asked for password,leave blank,click OK
reboot,and their should not be a content password

Maybe more information is usefully:
What OS is installed on these workstations?
You work on an NT domain?
Your problem look like as a mandatory profile (not allow any changes in user profile - NTUSER.MAN).
Check if the problems is present with other account (NTUSER.DAT)
Also you can check if you use, options for security policies.
Other possibility is if you have installed on these workstation a custom IE made with IEAK.