Click Start, point to Run and type "dcpromo.
The wizard windows will appear. Click Next.
In the Operating System Compatibility windows read the requirements for the domain's clients and if you like what you see - press Next.
Choose Domain Controller for a new domain and click Next.
Choose Create a new Domain in a new forest and click Next.
Enter the full DNS name of the new domain, for example - san.com - this must be the same as the DNS zone you've created in step 3, and the same as the computer name suffix you've created in step 1. Click Next
This step might take some time because the computer is searching for the DNS server and checking to see if any naming conflicts exist.
Accept the the down-level NetBIOS domain name, in this case it's san. Click Next
Accept the Database and Log file location dialog box (unless you want to change them of course). The location of the files is by default %systemroot%\NTDS, and you should not change it unless you have performance issues in mind. Click Next
Accept the Sysvol folder location dialog box (unless you want to change it of course). The location of the files is by default %systemroot%\SYSVOL, and you should not change it unless you have performance issues in mind. This folder must be on an NTFS v5.0 partition. This folder will hold all the GPO and scripts you'll create, and will be replicated to all other Domain Controllers. Click Next.
If your DNS server, zone and/or computer name suffix were not configured correctly you will get the following warning:
This means the Dcpromo wizard could not contact the DNS server, or it did contact it but could not find a zone with the name of the future domain. You should check your settings. Go back to steps 1, 2 and 3. Click Ok.
You have an option to let Dcpromo do the configuration for you. If you want, Dcpromo can install the DNS service, create the appropriate zone, configure it to accept dynamic updates, and configure the TCP/IP settings for the DNS server IP address.
To let Dcpromo do the work for you, select "Install and configure the DNS server...".
Click Next.
Otherwise, you can accept the default choice and then quit Dcpromo and check steps 1-3.
If your DNS settings were right, you'll get a confirmation window.
Just click Next
Accept the Permissions compatible only with Windows 2000 or Windows Server 2003 settings, unless you have legacy apps running on Pre-W2K servers.
Enter the Restore Mode administrator's password. In Windows Server 2003 this password can be later changed via NTDSUTIL. Click Next.
Review your settings and if you like what you see - Click Next.
See the wizard going through the various stages of installing AD. Whatever you do - NEVER click Cancel!!! You'll wreck your computer if you do. If you see you made a mistake and want to undo it, you'd better let the wizard finish and then run it again to undo the AD.
all went well you'll see the final confirmation window. Click Finish
You must reboot in order for the AD to function properly
Checking the AD installation
You should now check to see if the AD installation went well.
First, see that the Administrative Tools folder has all the AD management tools installed.
Run Active Directory Users and Computers (or type "dsa.msc" from the Run command). See that all OUs and Containers are there.
Run Active Directory Sites and Services. See that you have a site named Default-First-Site-Name, and that in it your server is listed
Open the DNS console. See that you have a zone with the same name as your AD domain (the one you've just created, remember? Duh...). See that within it you have the 4 SRV record folders. They must exist.
If they don't (like in the following screenshot), your AD functions will be broken (a good sign of that is the long time it took you to log on. The "Preparing Network Connections" windows will sit on the screen for many moments, and even when you do log on many AD operations will give you errors when trying to perform them).
= Bad
This might happen if you did not manually configure your DNS server and let the DCPROMO process do it for you.
Another reason for the lack of SRV records (and of all other records for that matter) is the fact that you DID configure the DNS server manually, but you made a mistake, either with the computer suffix name or with the IP address of the DNS server (see steps 1 through 3).
To try and fix the problems first see if the zone is configured to accept dynamic updates.
Right-click the zone you created, and then click Properties
On the General tab, under Dynamic Update, click to select "Nonsecure and secure" from the drop-down list, and then click OK to accept the change.
You should now restart the NETLOGON service to force the SRV registration.
You can do it from the Services console in Administrative tools
Or from the command prompt type "net stop netlogon", and after it finishes, type "net start netlogon".
Let it finish, go back to the DNS console, click your zone and refresh it (F5). If all is ok you'll now see the 4 SRV record folders.
If the 4 SRV records are still not present double check the spelling of the zone in the DNS server. It should be exactly the same as the AD Domain name. Also check the computer's suffix (see step 1). You won't be able to change the computer's suffix after the AD is installed, but if you have a spelling mistake you'd be better off by removing the AD now, before you have any users, groups and other objects in place, and then after repairing the mistake - re-running DCPROMO.
Check the NTDS folder for the presence of the required files.
Check the SYSVOL folder for the presence of the required subfolders.
Check to see if you have the SYSVOL and NETLOGON shares, and their location.
all of the above is ok, I think it's safe to say that your AD is properly installed.