Start a specific service on all SharePoint Servers in a FARM (WFE and APP Servers) using PowerShell
//Services Like SPTimerV4, SPAdminV4, iisadmin, W3SVC, WAS
$serviceName = "Name of the service to be started"
// Loop thru all the servers in a SharePoint Farm
foreach ($server in (get-spserver | Where {$_.Role -ne "Invalid"}) )
{
Write-Host Restarting $serviceName in $server.Name
$service = Get-WmiObject -computer $server.Name Win32_Service -Filter "Name='$serviceName'"
$service.InvokeMethod('StopService',$Null)
Start-Sleep -s 5
$service.InvokeMethod('StartService',$Null)
Start-Sleep -s 5
$service.State
}