Query UAC Status (http://www.ehloworld.com/1026)

Get-UACStatus_registry.ps1

function Get-UACStatus {
	<#
	.SYNOPSIS
	    Gets the current status of User Account Control (UAC) on a computer.

	.DESCRIPTION
	    Gets the current status of User Account Control (UAC) on a computer. $true indicates UAC is enabled, $false that it is disabled.

	.NOTES
	    Version      			: 1.0
	    Rights Required			: Local admin on server
	    					: ExecutionPolicy of RemoteSigned or Unrestricted
	    Author(s)    			: Pat Richard (pat@innervation.com)
	    Dedicated Post			: http://www.ehloworld.com/1026
	    Disclaimer   			: You running this script means you won't blame me if this breaks your stuff.

	.EXAMPLE
		Get-UACStatus

		Description
		-----------
		Returns the status of UAC for the local computer. $true if UAC is enabled, $false if disabled.

	.EXAMPLE
		Get-UACStatus -Computername mycomputer

		Description
		-----------
		Returns the status of UAC for the computer specified via -Computer. $true if UAC is enabled, $false if disabled.

	.LINK
	  http://www.ehloworld.com/1026

	#Requires -Version 2.0
	#>

	param(
		[parameter(ValueFromPipeline = $true, ValueFromPipelineByPropertyName = $true, Mandatory = $false)]
        	[Alias("Computer","__Server","IPAddress","CN","dnshostname")]
		[string[]]$Computername = $env:COMPUTERNAME
	)
    
    BEGIN {
	    $RegistryValue = "EnableLUA"
	    $RegistryPath = "Software\Microsoft\Windows\CurrentVersion\Policies\System"
	    $UACStatus = $false
    }

    PROCESS {
        foreach($Computer in $Computername)
        {            
            try {
                $UACStatus = $Null
                $OpenRegistry = [Microsoft.Win32.RegistryKey]::OpenRemoteBaseKey([Microsoft.Win32.RegistryHive]::LocalMachine,$Computer)
	        $Subkey = $OpenRegistry.OpenSubKey($RegistryPath,$false)
                $UACStatus = [bool]($Subkey.GetValue($RegistryValue))
            }
            catch [System.Management.Automation.MethodInvocationException] {
                Write-Warning -Message "Error accessing [$Computer] - host is down or does not exist"
            }
            Catch [System.Security.SecurityException] { 
                Write-Warning -Message "Error accessing [$Computer] - please verify access permissions"
            }
            finally {
                New-Object psobject -Property @{
                    Computername = $Computer
                    UACEnabled = $UACStatus
                }
            }
        }
    }
} # end function Get-UACStatus


Get-UACStatus
$env:COMPUTERNAME,"doesnotexist" | Get-UACStatus
Get-WmiObject win32_operatingsystem | Get-UACStatus
Get-UACStatus -Computername $env:COMPUTERNAME,"doesnotexist"

Get-UACStatus_winrm.ps1

function Get-UACStatus {
	<#
	.SYNOPSIS
	    Gets the current status of User Account Control (UAC) on a computer.

	.DESCRIPTION
	    Gets the current status of User Account Control (UAC) on a computer. $true indicates UAC is enabled, $false that it is disabled.

	.NOTES
	    Version      			: 1.0
	    Rights Required			: Local admin on server
	    					: ExecutionPolicy of RemoteSigned or Unrestricted
	    Author(s)    			: Pat Richard (pat@innervation.com)
	    Dedicated Post			: http://www.ehloworld.com/1026
	    Disclaimer   			: You running this script means you won't blame me if this breaks your stuff.

	.EXAMPLE
		Get-UACStatus

		Description
		-----------
		Returns the status of UAC for the local computer. $true if UAC is enabled, $false if disabled.

	.EXAMPLE
		Get-UACStatus -Computername mycomputer

		Description
		-----------
		Returns the status of UAC for the computer specified via -Computer. $true if UAC is enabled, $false if disabled.

	.LINK
	  http://www.ehloworld.com/1026

	#Requires -Version 2.0
	#>

	param(
		[parameter(ValueFromPipeline = $true, ValueFromPipelineByPropertyName = $true, Mandatory = $false)]
        	[Alias("Computer","__Server","IPAddress","CN","dnshostname")]
		[string[]]$Computername = $env:COMPUTERNAME
	)
    
    PROCESS {
        foreach($Computer in $Computername)
        {            
            try {
                $UACStatus = [bool](Invoke-Command -ComputerName $Computer -ScriptBlock {
                    (Get-ItemProperty -Path 'HKLM:\Software\Microsoft\Windows\CurrentVersion\Policies\System' -Name 'EnableLUA').EnableLUA
                } -ErrorAction Stop) 
            }
            catch {
                Write-Warning -Message "Error accessing [$Computer] - host might is down or does not exist"
                $UACStatus = $Null
            }
            finally {
                New-Object psobject -Property @{
                    Computername = $Computer
                    UACEnabled = $UACStatus
                }
            }
        }
    }
} # end function Get-UACStatus


Get-UACStatus
$env:COMPUTERNAME,"doesnotexist" | Get-UACStatus
Get-WmiObject win32_operatingsystem | Get-UACStatus
Get-UACStatus -Computername $env:COMPUTERNAME,"doesnotexist"

Pipeline_usage.ps1

Get-UACStatus | where{$_.UACEnabled -eq $true} | Set-UACStatus -Enabled:$false