You might encounter this common problem when you reinstall the Windows operating system on a client: The client no longer can log into the network. Apparently the machine name is unchanged from before, and the user name and passwords are also correct. You also find that it doesn't matter what level of privileges the user has, the system can't log in, even though the domain controller clearly shows the system by the system name you are using.
Windows recognizes systems not only by the system name, but also by the internal system ID. If the installation or upgrade has changed this internal ID, the domain server will not recognize the system. This method is used to prevent people from gaining access to a domain on a particular machine by simply renaming a system.
The solution is to log on to the server with admin privileges, and then remove the system name from the list of computers on the domain server. Then, on the client, log on with admin privileges, right click on the Computer icon and select Properties. Click on the Computer Name tab, then on the Network ID tab, and launch the Network Identification wizard. You can now join the domain under your previous system name.
Barrie Sosinsky is president of consulting company Sosinsky and Associates (Medfield, Mass.). He has written extensively on a variety of computer topics. His company specializes in custom software (database and Web related), training and technical documentation.
This was first published in January 2003