Prevent a shutdown of a Windows XP system

Prevent a shutdown of a Windows XP system
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This tip applies to both Windows XP Home and Windows XP Professional. Since editing the registry is risky, be sure you have a verified backup before saving any changes.
By default, at three o’clock every morning Windows XP’s Automatic Updates tool contacts the Windows Update site and automatically downloads and installs updates for your system. However, that can't happen if other people who use the computer shut it down at the end of the day. Fortunately, you can prevent anyone from shutting down Windows XP with a little registry tweak. Here’s how:
1. Launch the Registry Editor (Regedit.exe).
2. Go to HKEY_CURRENT_USER\ SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Explorer.
3. Right-click the Explorer subkey and select New | DWORD Value.
4. Name the key NoClose and press Enter twice.
5. Type 1 in the Value Data text box and click OK.
To enable the setting, close the Registry Editor and restart your system. Once your system restarts, you will not be able to it shut down by clicking the Shutdown button on the Start menu. This will prevent most users from inadvertently shutting down the computer.
When you do want to shut down your system, just access Task Manager by pressing Ctrl + Alt + Delete, then pull down the Shut Down menu and select the Turn Off command.