Hello ALL, Good evening. I'm new on this Forum. Owner of that Mac from december 2003 all was OK. From 2 months it will not reboot after a soft update or after the command "Command+Alt+P+R". The G5 arrest correctly but then don't reboot. I must then switch off and after any minutes start it … That always the same with one of the two internal disks SATA or with one of the two external disks Firewire. And also with Mac OS X Tiger 10.4.11 or Leopard 10.5.8. A control with "Apple Hardware Test" don't seen anything ! Has someone one idee or better a remedy ? Thank you for your reading. Cordially. Pierre Moello.