Enable / disable the Ctrl +Alt+Del from logon screen ?

Do the following ...

1. Start the registry editor (regedit.exe)
2. Move to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows
   NT\CurrentVersion\Winlogon
3. Double click on DisableCAD (create of type REG_DWORD if it does not exist)
4. Set to 1 if you don't want to have to press Ctrl-Alt-Del, and set to 0 if you do. Click OK
5. Close the registry editor
6. Reboot the machine