I am having trouble booting after installing the Leopard Graphics Update. I am running on Aluminum 15" Powerbook G4 1.67Ghz. Since I have installed the update it boots to the blue screen where it just hangs for as long as I leave it. I have been able to successfully boot in safe boot mode and that is how I am writing this now, but if I try to run disk utility everything freezes up. Does anyone have any ideas?