In order to get the option to manage users, computers, etc in AD you need to have the AD tools installed.
This is a 2 step process.
The first step is you need to install the Remote Server Administration Tools for Windows 7 with SP 1.
The second step is to enable the AD tools in control.
From the control panel, click Programs and Features.
Select Turn Windows Features on or off (on the left side)
Under Remote Server Administration Tools –> Role Administration Tools, select AD DS and AD LDS Tools.
Select the Active Directory Administrative Center.
Now under the Start menu –> Administrative Tools you will find your AD tools