Change the strong password policy of Windows 2003

We may encounter the following error when using a simple password for a user in Active Directory:
Windows cannot set the password for <user> because: The password does not meet the password policy requirements. Check the minimum password length, password complexity and password history requirements.

We can change the password policy of Windows Server 2003.
The detail steps are introduced in:
http://www.tacktech.com/display.cfm?ttid=354

Maybe we need to restart system to apply the changed security policy.