If you would like to restrict access to restricted web sites, Internet Explorer makes this possible by adding a supervisor password to the Content Advisor. Here's how:

Open Internet Explorer, then go to Tools>> Internet Options>> Content tab>> Enable tab (under the Content Advisor section)>> General button (in the Content Advisor window)>> Create Password button (under Supervisor Password section).

If you should forget your password, there is a way to work around this issue, here's how:
Warning: The following instructions involves editing the Windows registry. Incorrect editing can have severely adverse effects on your operating system. I recommend that you do a backup of the Windows registry prior to making any modifications.

Go to Start>> Run. Type in: regedit [Enter] or click OK.
Drill down to the following registry key:

HKEY_LOCAL_MACHINE\SOFTWARE\MICROSOFT\WINDOWS\CURRENTVERSION\POLICIES\RATINGS

1.Right click on the "Ratings" entry and then select Delete. Exit the Registry editor.
2.Now you can open IE and disable the Content Advisor.
3.Once you are prompted for the Supervisor Password, leave the password box blank and then click OK.
4.You can now re-enable the Content Advisor feature and create a new Supervisor Password.