Set-ServiceStartupMode [For PowerShell v2+]

Set-ServiceStartupMode.ps1

# For PowerShell v2; Otherwise, Set-Service cmdlet exists in v3+ with -StartupType parameter!
function Set-ServiceStartupMode {
[CmdletBinding()]
param (
  [String[]]$ComputerName,
  [String]$ServiceName,
  [ValidateSet("Boot","System","Automatic","Manual","Disabled")]
  [String]$StartupMode,
  [Parameter(Mandatory=$False)]
  [Management.Automation.PSCredential]$Credential
)
  Invoke-Command -ComputerName $ComputerName -Credential $Credential -ScriptBlock {
      $Service = Get-WmiObject win32_service -Filter "Name=`'$($args[0])`'" #Retrieve
      if ($Service) {
          $NULL = $Service.ChangeStartMode("$($args[1])") #Change
          $Service | select Name,Status,StartMode #Verify
      }
      else {
        Write-Error "$($args[0]) not found."
      }
  } -ArgumentList $ServiceName,$StartupMode
}

# Example use of function
$ServerLists = @("srv100","srv101","srv102","srv103")
Set-ServiceStartupMode -ComputerName $ServerLists `
                       -ServiceName winrm `
                       -StartupMode Automatic `
                       -Credential (Get-Credential) # For alternate credentials