Aqui está o AutoHotKey Script que faz isso. Certifique-se de executar este script na inicialização. (Adicione um atalho na pasta de inicialização)
;
; AutoHotkey Version: 1.x
; Language: English
; Platform: Win9x/NT
; Author: AEonAX
;
#NoEnv ; Recommended for performance and compatibility with future AutoHotkey releases.
SendMode Input ; Recommended for new scripts due to its superior speed and reliability.
SetWorkingDir %A_ScriptDir% ; Ensures a consistent starting directory.
if (A_Hour=5 and A_Min>55 and A_Min<59) ;Check if script starting time between 05:55 and 05:59 (24Hr clock)
{
Sleep,1000*60*5 ;Waits 5 Minutes
msgbox,4,,Will Shutdown in 60 seconds. Do you want to Stop the Shutdown.,60 ;Shows a msgbox for 60 seconds, If no response then shutsdown
ifmsgbox,Yes
MsgBox Shutdown Cancelled
else
Shutdown,1
}