In my quest to fix my messed up mac ( started here: http://forums.macrumors.com/showthread.php?t=403016 ) I have found that my computer startup disk is messed up-there is always a question mark on the startup disk when i check it on system preferences and I can only start my computer in safe mode, boot mode, and every other mode but it won't just start up regularly. I ran Onyx and it said that my startup disk needed to be repaired so I checked it/repaired it with disk utility and everything was fine. I then booted from my install disk and again there was a question mark on the startup disk-i repair it there and iot says everything is ok. Also, when i boot in safe mode the system profiler does not find my core audio (built in audio) or my airport. and help/advice? I tried applejack as well and it got stuck on "repair permissions" for a few hours before i stopped it.