The term 'Get-ADUser' is not recognized as the name of a cmdlet

I have used the following query to list the users in a windows 2008 server, but failed and got the below error.

$server='client-pc-1';$pwd= convertto-securestring 'password$' -asplaintext -
force;$cred=new-object  -typename System.Management.Automation.PSCredential -argumentlist 'Administrator',$pwd; invoke-command -computername $server -credential 
$cred -scriptblock {Get-ADUser -Filter (enabled -ne $true)}

The exception is given below...Can anyone help me to solve this?

The term 'Get-ADUser' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the
spelling of the name, or if a path was included, verify that the path is correct 
and try again.
    + CategoryInfo          : ObjectNotFound: (Get-ADUser:String) [], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException

If the ActiveDirectory module is present add

import-module activedirectory

before your code.

To check if exist try:

get-module -listavailable

ActiveDirectory module is default present in windows server 2008 R2, install it in this way:

Import-Module ServerManager
Add-WindowsFeature RSAT-AD-PowerShell

For have it to work you need at least one DC in the domain as windows 2008 R2 and have Active Directory Web Services (ADWS) installed on it.

For Windows Server 2008 read here how to install it

Check here for how to add the activedirectory module if not there by default. This can be done on any machine and then it will allow you to access your active directory "domain control" server.

EDIT

To prevent problems with stale links (I have found MSDN blogs to disappear for no reason in the past), in essence for Windows 7 you need to download and install Remote Server Administration Tools (KB958830). After installing do the following steps:

• Open Control Panel -> Programs and Features -> Turn On/Off Windows Features
• Find "Remote Server Administration Tools" and expand it
• Find "Role Administration Tools" and expand it
• Find "AD DS And AD LDS Tools" and expand it
• Check the box next to "Active Directory Module For Windows PowerShell".
• Click OK and allow Windows to install the feature

Windows server editions should already be OK but if not you need to download and install the Active Directory Management Gateway Service. If any of these links should stop working, you should still be able search for the KB article or download names and find them.

get-windowsfeature | where name -like RSAT-AD-PowerShell | Install-WindowsFeature