strComputer = "."
Set objWMIService = GetObject("winmgmts:" _
  & "{impersonationLevel=impersonate,(Shutdown)}!\\" & strComputer & "\root\cimv2")
Set colOperatingSystems = objWMIService.ExecQuery _
  ("Select * from Win32_OperatingSystem")
For Each objOperatingSystem in colOperatingSystems
  ObjOperatingSystem.Reboot()
Next