First take a fresh installation of Windows Server 2008.

 
1. Go to the "Server Manager" MMC.

Right Click "Roles" and Select "Add Roles".

2. When the wizard is displayed Click Next.

3. Select the "Active Directory Domain Services" role and Click Next.

4. If you are new to Active Directory Domain Services, I suggest you read the information on this wizard screen. Click Next.

5. The role will be installed, however Active Directory Domain Services itself will start and seperate installation wizard called DCPROMO.EXE. Click Close.

6. Tick "Use advanded mode installation" and Click Next.

7. Review the operating system compatability message about Windows NT 4.0 cryptography algorithms no longer supported and access if this applies you. Click Next.

8. Select "Create a new domain in a new forest". Click Next.

9. Enter a fully qualified domain name (FQDN) for your domain. Click Next.

10. Accept the NETBIOS name of the domain. Click Next.

11. Review the correct Forest functional level for your new Forest. Select the Level and Click Next.

12. Review the correct Domain functional level for your new Domain. Select the Level and Click Next.

13. Tick "DNS server" in the additional options for the domain controller. This will install and configure this DC also as a DNS server for your domain. Click Next.

14. If there are no authorative DNS servers for your domain this will be confirmed with the message below. This means it is now aware it is setting up an new delegation to itself for DNS queries for your domain. Click Yes.

15. Configure the locations for the Database folder, Log files folder and SYSVOL folder. Click Next.

16. Enter and confirm the password which will be used for Directory Service Restore Mode. This applies only to this DC. Click Next.

17. Review the settings and Export to a file if required. Click Next.

; DCPROMO unattend file (automatically generated by dcpromo)
; Usage:
;   dcpromo.exe /unattend:C:\Users\Administrator\Desktop\LON-DC1-contoso.com.txt
;
[DCInstall]
; New forest promotion
ReplicaOrNewDomain=Domain
NewDomain=Forest
NewDomainDNSName=contoso.com
ForestLevel=2
DomainNetbiosName=CONTOSO
DomainLevel=2
InstallDNS=Yes
ConfirmGc=Yes
CreateDNSDelegation=No
DatabasePath="C:\Windows\NTDS"
LogPath="C:\Windows\NTDS"
SYSVOLPath="C:\Windows\SYSVOL"
; Set SafeModeAdminPassword to the correct value prior to using the unattend file
SafeModeAdminPassword=
; Run-time flags (optional)
; RebootOnCompletion=Yes

18. Active Directory Domain Services and DNS will be installed. Tick "Reboot on completion".

19. The server will reboot and the logon screen will be displayed (witht he domain appended to the user name).

Enter the administrator password and hit Enter.

20. The "Server Manager" will be displayed.

Both the Active Directory Domain Services and DNS Roles can be managed via this console.