I have installed MS virtual machine 2007 on a winxp sp2, and installed win2008std server on the virtual machine. On win2008 DC, I installed AD and DNS, configured IP to same network with winxp computer. from winxp, i can ping win2008 server, DNS is poiting to win2008 server. But when I tried to join winxp to the domain, it returned the error: access denied??? even I tried with admin account :mydomain\administrator Any suggestion would be appreciated.

Are you able to ping the Fully Qualified Domain Name (FQDN) of your domain from the Windows XP machine? For example: ping mydomain.local

Hello, Thank you for your post. Based on my research, this issue might be caused by the reason that the Administrators do not have Read/Write access to the Windows Time and/or Netlogon services on your XP client PC. To resolve this issue, check the following: 1. Get a GPRESULT /Z on the member machine and see which GPO is setting explicit permissions in System Services ('Computer config | Windows settings | security settings | system services') 2. Verify that Administrators and System have full control to the W32time and Netlogon registry subkeys (Right click the following registry key folders and click permissions) Hkey_local_machine\system\currentcontrolset\services\w32time Hkey_local_machine\system\currentcontrolset\services\netlogon 3. If the settings are coming from a GPO, change the permissions so that Administrators (or whatever user needs rights to join/disjoin) have Full Control 4. Force a policy refresh. I hope this helps.If the problem still occurs, please let me know. :)