Question : Transfer XP Pro client membership from workgroup to Domain

In our local small library I have a network of XP machines including 20 client machines and a Windows 2003 Server. 18 Of the clients are connected as members of the only LAN present.  2 of the machines are currently members of a workgroup. These 2 were previously members of the domain.  Trying to connect either of these 2 clients to the LAN by data entry in the System Properties>Computer Name >Change screen fails with notice that the Domain Controller for the LAN is not available for connection.

IPConfig /all for all machines reads correctly except that second line under Windows IP configuration: Primary Dns Suffix does not return LAN name.  All machines Ping successfully in both directions. Network cards have been replaced to assure this is not a hardware problem.

With several local consultants failing to identify this issue over several days we need some help!  Is there any software in the WindowsServer 2003 that could have been configured to limit the number of clients allowed to join the domain.  Other ideas?

Answer : Transfer XP Pro client membership from workgroup to Domain

In the DNS entries in LAN settings
Just add the IP of your Server in primary DNS.
remove other entry i.e. Alternate DNS
Then restart the system
and retry adding it to the domain.
Please share ipconfig /all of both the system on workgroup and domain as well.

Regards,
Navneet