Self-rescheduling task

TheTask.ps1

$taskScript = {
    # Do your stuff, start the service, ...
    Start-Service -Name TheCrashingService

    $triggers = @(
        New-ScheduledTaskTrigger -Once -At (Get-Date).AddHours(12)
        New-ScheduledTaskTrigger -AtLogOn -User 'someone'
    )

    $task = Get-ScheduledTask -TaskName YourScheduledTask

    # Reset triggers to AtLogon trigger
    if ($task.Triggers.Count -eq 2)
    {
        $triggers = New-ScheduledTaskTrigger -AtLogOn -User 'someone'
    }

    Set-ScheduledTask -TaskName YourScheduledTask -Trigger $triggers
}

$taskScript.ToString() | Set-Content .\MyTask.ps1

$triggers = New-ScheduledTaskTrigger -AtLogOn -User 'someone'
$action = New-ScheduledTaskAction -Execute (Join-Path $PSHome powershell.exe) -Argument "-File `"$(Resolve-Path .\MyTask.ps1)`""
$task = New-ScheduledTask -Action $action -Trigger $triggers -Description 'Does things'
$task | Register-ScheduledTask -TaskName YourScheduledTask