Multiple shutdown attempts

I am having the same problem.
I click: [Start], [Shutdown], [Shutdown Computer] and it
goes through the motions of shutting down but then comes
back up again. It acts as though I have clicked [Re-Start]
instead of [Shutdown]. After it goes through the shutdown
process one time, I have to hold the Power button down
until it really does power down. What is happening here?

-----Original Message-----
I have two XP machines on my home network and after
several months of adding hardware & software, I have
found that seldom can I shut down the PCs on the
first attempt. After a second attempt, the "turn off"
button works...What''s the deal?
.