Registry changes to HKU\.Default or HKCU during installation of windows, BEFORE the first logon are incorporated in the %SystemDrive%\Documents and Set-tings\Default User\NTUSER.DAT. New user profiles, including Local System, Local Services, and Network Services, are replicated from %SystemDrive%\Documents and Settings\Default User, and that includes .\NTUSER.DAT. That file is completely built before the first user logon, and cannot be edited directly by one of the registry editors (HKU\.Default is the Local System profile!). To modify %SystemDrive%\Documents and Settings\Default User\NTUSER.DAT, it must be loaded into HCU with a new key name, followed by applying modifications under that key and unloading. This can be automated with the Reg.exe command line utility.