Last night I went to turn off my computer, running Mandrake 9.1, and it would not shut down correctly. When I selected shut down, it went from the KDE desktop to a blank screen and then shut the monitor off all in about 2-3 seconds.

It used to shut down correctly (unload everything), all except actually shutting the computer off. I'm not sure what I did. The only programs I installed since the last time I shut it down (that I can think of) was Americas Army. It didn't install right, but that is another story.

I'm new to Linux, and have enjoyed my experience so far. On the other hand though, I seem to manage to screw somthing up every week. I'm thinking about going back to a dual boot WinXP and MDK 9.1.

I don't know if this will work , but try alt ctl del that forces the system down then when it says rebooting..... go ahead and try hitting the power button

To shutdown your machine you must type in console:
shutdown -h now (halt after shutdown.)
shutdown -r now (reboot after shutdown.)
Its very simple and the system shutsdown correctly ;]~ it stops all processes running before shutting down...