How to install Active Directory Users and Computers for Windows 2008 and R2

Active Directory Users and Computers allows management of users, groups, organizational units, and all other AD DS objects of your domain. 

To install Active Directory users and computers you will have to launch the server manager. You can type in "ServerManager.msc" in Run prompt and hit enter(OK).

Under Server manager select Features. The click on Add Features. Add Feature will launch the Add Feature Wizard listing the features to add. 

On Windows Server 2008, under Add Feature Wizard expand 

• Remote Server Administration Tools
• Role Administration Tools
• Active Directory Domain Services Tools 

and then select Active Directory Domain Controller Tools which include Active Directory Users and Computers, Active Directory Domains and Trusts etc...

On Windows Server 2008 R2, under Add Feature Wizard expand

• Remote Server Administration Tools
• Role Administration Tools
• AD DS and AD LDS Tools
• AD DS Tools
• AD DS Snap-Ins and Command-Line Tools.

On selecting these features complete the Wizard to install the selected features.