i have old windows 2003 server in domain, and i have installed windows 2008 server in another machine i want to migrate all users from 2003 to 2008, including active directory thanks saud

You have place your question in wrong forum. Use Windows Server forum instead http://social.technet.microsoft.com/Forums/en/winserverDS/threads?filter=unanswered For migration, there are migration documents on Microsoft technet and document download pages. In short: 1. Source AD must meet some criteria, namely the domain/forest level 2. You should prepare the source domail controller(s) by applying ADPREP for forest, domain and possibly for gpo. Regards Milos