HOW do you turn off your Ubuntu boxes?

[Gerry Visel]

   Since I upgraded to Edgy, my computer will not turn off when I "shut
it down."  It goes to the Kubuntu desplash screen, walks across its
progress bar, flashes a black screen, and then returns to the splash
screen and sits.  No drive activity thereafter.  I have to hold the
power switch down for five seconds to shut it down.

   Dapper behaved properly and shut off the box after the desplash
screen progress bar got to the end.  

   Is there something I can do to get this behavior back?

Thanks,
Gerry