For Windows 2000, Windows 2003
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GPRESULT.EXE /?
Microsoft (R) Windows (R) 2000 Operating System Group Policy Result tool
Copyright (C) Microsoft Corp. 1981-1999
This tool displays the result of Group Policy for the current user and computer.
usage: gpresult [/V] [/S] [/C | /U] [/?]
/V Verbose mode
/S Super verbose mode
/C Computer settings only
/U User settings only
For Windows XP
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use the Resultant Set of Group Policy snap-in
%systemroot%\system32\rsop.msc