Windows2000 professional (shutdown)

hello, I have two computers running windows 2000 professional. They are all installed on ATX system case. During the shutting down processing, one of them will shutdown automatically, but one of them will not and it will display messages saying that “it is now safe to turn off your computer”. In this case, I have to shut it down manually from the power botton. What could I do to shut down the system automaticlly like other installed on ATX system case?

Thanks
Dan Williams