On Windows 2008 R2, If I perform the following from Powershell, I get the following FQDN:
PS C:\t> (gwmi WIN32_ComputerSystem).Name + "." + (gwmi WIN32_ComputerSystem).Domain
At this point I have added a role of ADDS, but I have not yet run the install (dcpromo.exe)
If I need to for any reason, how do I change the FQDN of the Windows machine?