XP Pro shutdown

I recently installed Windows XP Pro on a Compaq 5304 with 128MB RAM, running a CyrixII 233Mhz. Everything installed just fine, but when I want to shut it down, it no longer powers off on it’s own. It brings me to the screen “It is now safe to turnoff your computer”. What can I do to it so that it shuts down the computer automatically? Any suggestions would be great help. Thanks in advance.