Add Win 2000 user to Win XP Admin Grp

I have a Windows 2000 server. Purchased a new PC with Windows XP.

I added the PC to the domain and can logon as any user of the domain.

I need to add a user to the local Administrators Group on the XP machine. I logged on as the domain administrator and attempted to add the user, but get an error that the domain cannot be found. I have connectivity because I can browse shared folders.

I’m doing this the same way as on the Windows 2000 PCs.

I also notice slow logons. There’s only 7 PCs on the switch with the server. All Windows 2000 Pro PCs are okay.

I have removed the PC from the domain and re-added it. I’ve also tried adding the user to the Power User Group with no luck.