Today tip is very useful particularly for those users who want to restrict the common users to shutdown public computer in common areas. You can disable the “Turn off Computer” button on the start menu and a common user will not “Turn Off, Restart and Stand By” a computer. Using registry editor, you can implement this task in all windows XP versions with minimum effort.
Follow the given steps to disable Turn off Computer” button on the start menu:
To use this feature, you will need to be logged into your computer with administrative rights.
Click Start button and type regedit in Run option then press Enter for next. 
How to disable Right click on Desktop
Follow the given steps to disable the right click functionality on desktop:
To use this feature, you will need to be logged into your computer with administrative rights.
Click Start button and type regedit in Run option then press Enter for next.
Windows Desktop Tips & Tricks
Windows: Desktop
Make the background of desktop icons transparent (XP)
Control Panel > System > Advanced > {Performance} Settings. On the Visual Effects tab, check Use drop shadows for icon labels on the desktop.
Restore My Documents folder if deleted (98)
To restore My Documents to the Desktop, click Start, then Run, and type:rundll32 mydocs.dll, RestoreMyDocsFolder