we ran into a permissions issue yesterday. "custom" permissions popped up and all went to h... in a handbasket. couldn't reboot my mac from my hd. had to reboot from install disk because when trying to reboot normally i'm getting the 'no' (ghostbuster) sign on the startup window. so, i've backed up my mac hd drive to an external via disk utility, saving my files. how to proceed from here i don't know...can someone help?