Hi, I have a G5 with dual 2.5 ghz running the latest leopard and it gets hung up during start up. The login window never appears and I just see a blue screen and no cursor. The computer was working 3 hours ago. I have put the 10.5 cd in and restarted with the "c" button held down and it wont start from the cd. Same blue screen. I tried re starting with the shift button held dow, I get to the blue screen, and my cursor shows, but nothing more.