MCSE Guide
GPO inherited from AD is refreshed on the computers by several ways:
Logon to computer (If the settings are of "user settings" in GPO)
Restart of the computer (If the settings are of "computer settings" in GPO)
Every 60 to 90 minutes, the computers query their DC for updates.
Manually by using gpupdate command. You can add the /force switch to force all settings and not only the delta.
Note: Windows 2000 doesn't support the Gpupdate command so you need run a different command instead:
