Have a look at these text and links... The first part is not for your problem, but if anybody has similar problems..
Note that these problems are discussed at length in Window Support forums, so most links come from there;
POWERDOWN ISSUES
"Powerdown issues" are quite distinctive from "shutdown issues." I define a shutdown problem as one wherein Windows doesn't make it at
least to the "OK to shut off your computer" screen. If Windows gets that
far, or farther, then it has shut down correctly. However, the computer
may not powerdown correctly after that. This is a different problem, and
I encourage people reporting these issues to make a clear distinction in
their labeling.
When Windows XP won't powerdown automatically, the APM/NT Legacy Power
Node may not be enabled. To enable this, right-click on the My Computer
icon, click Properties | Hardware | Device Manager | View. Check the box
labeled "Show Hidden Devices." If it's available on your computer, there
will be a red X on the APM/NT Legacy Node. Try enabling it and see if
this resolves the powerdown problem (Tip from Terri Stratton). Or, to
check the other side of the APM/ACPI coin, open the Power Options applet
in Control Panel. If there is an APM tab, make sure the "Enable Advanced
Power Management Support" box is checked.
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Quick idea here. I had several problems with shutting down XP and tried many things to cure it. Eventually, I got adaware and rant it. I had over 85 spyware items on my PC and removed them all. XP shuts down fine now. It seems that some of them don't shut down properly and hang the OS.
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