To manually force Group Policy to refresh under Windows 2000, you use the command
secedit /refreshpolicy
Microsoft has replaced this command in Windows 2003 and XP with this command:
gpupdate
You can run this command without any switches to update both machine and user policies. When you run Gpupdate on Windows 2003, the machine will display the following:
Refreshing Policy… User Policy Refresh has completed. Computer Policy Refresh has completed. To check for errors in policy processing, review the event log.The last line doesn’t appear on XP machines. To update only the user command components, type
gpupdate /target:user
To load only the computer command components, type
gpupdate /target:computer
The optional switches that you can use with the Gpupdate command are
/Force. This switch loads all policy settings rather than just those that have changed.
/Wait:. This switch specifies the amount of time to wait for the policy processing to finish before returning to the command prompt.
/Logoff. This switch causes the user to log off after Group Policy refreshes.
/Boot. This switch causes a reboot after Group Policy refreshes.
/Sync. This switch synchronously (i.e., in the background) applies the next boot or user logon policy (the system will prompt you to log off or reboot, depending on the /target setting).
via How can I force Group Policy to refresh on a Windows Server 2003 or Windows XP machine?.