I just recently upgraded my Power Mac G5 from OS X Tiger to Leopard. When the installation completed, I restarted, after that, it just gives me a blank blue screen with a mouse pointer(which I can move), there is long pause, then you hear the hard drive, then it just stops. The screen is still there, nothing is happening. My G5 is the early 1.6 GHz model, it has 2 GB of RAM, and an 80 GB hard drive. I really don't know whats wrong, the longest it's been sitting like this was 2 min. I'm not sure if anything will happen next, I'll give you updates if something happens. If anyone has a fix, I would like to know. Thank you.