A mac that im working on goes to the grey screen then goes to the login screen. Before the usernames come up there is a blue bar that goes and it usually says "starting os x". On this machine the bar comes up but the system doesnt do anything. No blue ever comes up. Just sits there. I have done a filecheck , checked permissions, tried safe mode and none helped. The hardware has passed. I have also reset nvram. Anyother ideas besides a restore??