When you reinstalled SME you should have restored a backup from the SME server you had to take out of service, looks like you did a clean install, so the domain controller your clients are trying to connect to doesn't exist anymore. (I know your new server has the same name, but not the same security identifiers, so to a Windows client it is a different domain controller)
If you don't have too many clients the easiest route is:
logon to each Windows client, remove it from old domain and then join to the new domain. This may cause other problems, for example with data.
If you have lots of clients I would try restoring a backup during the SME install.
The joys of running Windows domains!
Dave
You will probably have to join workgroup "xyz" and maybe reboot each client before you can join the new domain
