I wasn't sure if this was a hardware or software problem. Ok, so I plug in my iPod 4th generation, and my mac g5 running os x 10.5 leopard freezes and a screen shows up saying I need to restart the computer. Ok so I do that and the screen comes up again. I unplug and restart and everything is fine. Now, I plug in an external usb HD and once again, the same screen. I unplug and restart. Now, I try a flash drive, and again, this screen pops up. I need help so I can use my flash drives again! p.s. the screen is a transparent gray screen that slowly rolls down from the top of the computer and then it says your computer must be restarted please hold the power button.