Power Down the Computer After Shutdown
This tweak sets the XP machine to power off completely rather than stop at the prompt advising users it's now safe to power off the machine.
[Start] [Run] [Regedit]
Registry Key: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
Modify/Create the Value Data Type(s) and Value Name(s) as detailed below.

Data Type: REG_DWORD [Dword Value] // Value Name: PowerdownAfterShutdown
Setting for Value Data: [0 = Disabled / 1 = Enabled]
Exit Registry and Reboot

- srikanth dhanwada