I have previously written an summary of how to get rid of the shutdown button from the start menu
http://www.shvoong.com/internet-and-tech nologies/computers/1914082-xp-shutdown-button-removal/
Now I will tell you how to get rid of the shutdown button from the login screen
To remove the shutdown button on the log in screen
-Start
-Run
-Type regedit
- Naviagate to
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\system
- Change the value of the dword "shutdownwithoutlogon" to 0
- The shutdown button will vanish!!
I take no responsiblity for any harm that comes from using this