Function Remove-SCOMAgent
{

 [CmdletBinding()]
 Param
    (
        [Parameter(Mandatory=$true, Position=0)]
        [string]$MServer,
        [Parameter(Mandatory=$true, Position=1)]
        [string]$AgentName,
        [Parameter(Mandatory=$true, Position=2)]
        [string]$User,
        [Parameter(Mandatory=$true, Position=3)]
        [string]$Domain

    )

$Cred = Get-Credential -Message "password" -Username "$Domain\$User"
	


#Import-Module OperationsManager            
New-SCOMManagementGroupConnection -ComputerName $MServer -Credential $Cred
Start-Sleep -s 3

$administration = (Get-SCOMManagementGroup).GetAdministration();
Start-Sleep -Milliseconds 500
$agentManagedComputerType = [Microsoft.EnterpriseManagement.Administration.AgentManagedComputer];
$genericListType = [System.Collections.Generic.List``1]
$genericList = $genericListType.MakeGenericType($agentManagedComputerType)
$agentList = new-object $genericList.FullName
$agent = Get-SCOMAgent *$AgentName*

If(!($agent))
{
$message = "No agent found with name `"$AgentName`""
$message
exit
}

Start-Sleep -S 5
$agentList.Add($agent);

$genericReadOnlyCollectionType = [System.Collections.ObjectModel.ReadOnlyCollection``1]
$genericReadOnlyCollection = $genericReadOnlyCollectionType.MakeGenericType($agentManagedComputerType)
$agentReadOnlyCollection = new-object $genericReadOnlyCollection.FullName @(,$agentList);    
$administration.DeleteAgentManagedComputers($agentReadOnlyCollection);
}

Remove-SCOMAgent -MServer MyMS -AgentName serv1 -User Myaccount -Domain MyDomain