Hi! I'm in way over my head after promising to fix my father in laws power mac g5. When i press the power button everything seem normal. you hear the apple sound but after a short while the fans speed up the screen turns grey with a folder icon and a flashing question mark and then the apple logo appears. i have never been past this stage. i have paired the memory installed correctly and i have tried every memory combination possible. I have reset the Pmu and i have reset the pram. i also tried to remove the battery but that didn't help either. i also tried to boot from a system disc but nothing i hear the disc spinning but nothing happens. any suggestions? i am going crazy with this and it would mean so much to me getting this fixed for my father in law!