When adding a computer in Active Directory Users and Computers, you configure The following user or group can join this computer to a domain, but other users can join this computer to the domain?

The following user or group can join this computer to a domain option is only for Windows NT 5.x+ computers. If this computer is running Windows NT 4.0 Workstation, Windows 95, or Windows 98, or Windows Millennium Edition (Me), the restriction is NOT applied.