My Shutdown Menu is Missing?

Infopackets Reader Larry O. writes:

" Dear Dennis,

I'm running Windows 2000 Pro. When I try to shut down the machine by clicking on Start -> Shutdown, I no longer have the option to Shutdown, Restart, or Hibernate! In fact, the machine automatically does a restart, offering *no* choices when Start -> Shutdown is clicked. The only way I can actually shut this computer down is to either pull the plug from the outlet or to hit the sleep button on the keyboard. Any ideas? "

My Response: I have no idea on this one -- aside from maybe a Registry Tweak (where to start?) or, worse yet -- reinstall Windows! Anyone have a solution? Send me your answer (email here).