About 80 percent of the time, when I shutdown from within OS X, my system hangs up. The desktop disappears, as expected, and I get stuck at the point where the screen is all blue with the spinning rainbow circle in the upper right corner (it does not move with the mouse). It stays like that endlessly, forcing me to either type SHIFT-CONTROL-COMMAND (I think that's the combination) to restart or to press the button on my control strip to cut the power. Now and then the shutdown goes properly, with a fairly loud popping sound when the computer shuts off (I may be crazy, but it seems louder than the one when I shutdown from OS 9). Any suggestions on how I might get OS X to shut down smoothly each time? Oh, I've taken to logging out first, but that doesn't seem to help. Usually I can log off, but then when I click to shutdown or restart, I get stuck as described. Sometimes I get stuck before the logging off process is completed. This is on a beige G3/266 desktop that has been upgraded to 466 MHz via a new processor chip rather than a new card.