$Now = Get-Date

$Time = Get-Date -Hour 3 -Minute 0 -Second 0
$Tmrw = $Time.AddDays(1)

$sec = $tmrw - $now
$sec2 = $sec.Seconds + ($sec.Minutes * 60) + ($sec.Hours * 3600)

echo $sec2 sec


shutdown -r -t $sec2 -f

pause