Hi, I was hoping someone may be able to help, I have a PowerBook G4 1.67ghz, running 10.4.10 with two users, everytime I try to shutdown the machine it simply returns to the login menu, I have tried hitting the shutdown and reset options from that menu but the screen goes blue and then straight back to the login menu (I have tried shutting down from both users). I can turn off the machine by pressing and holding the power button, and it boots up fine after that, but it is getting frustrating that I can't turn it off normally. I have tried repairing permissions, and reseting the PRAM, I have also reinstalled the 10.4.10 update, even though this has started long after I installed the update perviously. Can anyone help, please! Thank you in advance, James.