I noticed that after I installled fedora (see signature), windows would not fully shut down the computer. It would say "Windows is shutting down...",
go black, and hang. I thought nothing of it, and would use the on/off button to shut the processor off.
But when I got the same computer to triple boot, Ubuntu did the same thing! It would say that it had shut down hda and hdb (there are only two hardrives), say "Power Down", not go black, and hang. Since the hardrives were/are off, I don't think pressing the off button hurts the computer, but I'm not sure. It seems that fedora has "master" control over the system, even when Ubuntu installed the grub that it currently uses.