Windows XP Stops Responding (Hangs) During Windows Shutdown
During shutdown or reboot, Win XP may hang (stop responding) at the saving your settings screen. During such a hang, there is no response to Ctrl+Alt+Del; the mouse may or may not work. The problem may be intermittent.
This is a known bug in Windows XP, for which Microsoft has a supported fix. Because this patch is scheduled for further quality assurance testing in the future, Microsoft only recommends that you install it if you have a serious problem; otherwise, they recommend waiting for Service Pack 1, which will include the more permanent version of the fix. To learn how to get this patch, see Windows XP Stops Responding (Hangs) During Windows Shutdown.
NOTE: The article says the patch may only be obtained by contacting Microsoft. However, it is now available on the Windows Update site under Recommended Updates for Win XP Professional, titled Restarting Windows XP.
As a workaround, you may resolve this problem by dismantling the Windows XP logon Welcome screen. In the Control Panel, click User Accounts, then click Change the way users log on or off. Uncheck the box that says Use the Welcome screen. This removes the initial logon screen with individual icons for each user and, instead, pops up the classic logon prompt that requires each user to type a user name and password.