i am working on a Mac G5 that has a apparent hard drive issue. When I start the G5 it chimes and the Apple logo appears and the little wheel just spins and spins and never loads the OS. When i remove the hard drive and replace it and reboot the G5 i now get a blinking folder with a question mark. I tried several different replacement drives and get the same question mark icon. However, when i put the original hard drive back in I at least get the Apple logo and the spinning wheel..but still no OS loads......what up with dat...???