Windows Task Scheduler task to shutdown the server after specified hours of idle time. This file can be imported in Windows Task Scheduler.

Auto shutdown task.xml

<?xml version="1.0" encoding="UTF-16"?>
<Task version="1.2" xmlns="http://schemas.microsoft.com/windows/2004/02/mit/task">
  <RegistrationInfo>
    <Date>2013-03-05T14:01:44.319601</Date>
    <Author>TRAIN1\Administrator</Author>
    <Description>Shut down the server after specified hours of idle time</Description>
  </RegistrationInfo>
  <Triggers>
    <IdleTrigger>
      <Enabled>true</Enabled>
    </IdleTrigger>
  </Triggers>
  <Principals>
    <Principal id="Author">
      <UserId>TRAIN1\Administrator</UserId>
      <LogonType>Password</LogonType>
      <RunLevel>LeastPrivilege</RunLevel>
    </Principal>
  </Principals>
  <Settings>
    <MultipleInstancesPolicy>IgnoreNew</MultipleInstancesPolicy>
    <DisallowStartIfOnBatteries>true</DisallowStartIfOnBatteries>
    <StopIfGoingOnBatteries>true</StopIfGoingOnBatteries>
    <AllowHardTerminate>true</AllowHardTerminate>
    <StartWhenAvailable>true</StartWhenAvailable>
    <RunOnlyIfNetworkAvailable>false</RunOnlyIfNetworkAvailable>
    <IdleSettings>
      <Duration>PT4H</Duration>
      <WaitTimeout>PT3H</WaitTimeout>
      <StopOnIdleEnd>true</StopOnIdleEnd>
      <RestartOnIdle>true</RestartOnIdle>
    </IdleSettings>
    <AllowStartOnDemand>true</AllowStartOnDemand>
    <Enabled>true</Enabled>
    <Hidden>false</Hidden>
    <RunOnlyIfIdle>true</RunOnlyIfIdle>
    <WakeToRun>false</WakeToRun>
    <ExecutionTimeLimit>P3D</ExecutionTimeLimit>
    <Priority>7</Priority>
  </Settings>
  <Actions Context="Author">
    <Exec>
      <Command>shutdown</Command>
      <Arguments>/s /f</Arguments>
    </Exec>
  </Actions>
</Task>