after choosing shutdown from the log in menu, computer displayed usual load of kill processes, etc, then system halted.
However, when I hit the power button, it continued to sit there and look at me.
I "solved" this by hitting the system's restart button, then booting into windows, then shutting down from there!
Was I just impatient? [I haven't played with the Linux os for a while...]
This happened in OpenLinux 2.3.