My PowerMac G5 has stopped Restarting and Shutting Down. When I click the blue Apple icon, and choose either restart or shutdown - nothing happens. I've force restarted a few times, repaired the disk and repaired permissions. The only way I can restart/shutdown is via terminal: "sudo shutdown -r now". The only thing I've done recently is to install MS Office 2004 SP2 and the Apple security update/iPod update. Anyone know whats going on?