I am helping a friend with his Mac. He experienced a total freeze/crash and now when he boots, his primary admin login keychain or account appears to be corrupted. When you enter an INCORRECT password, the dialogue "shakes" as per usual. When he enters the correct password it goes into an endless loop with a blue screen and the spinning "progress gear" (not beach ball) intermittently appearing and disappearing (and a slightly different shade of blue background). I helped him create a new user account from a single user boot using terminal commands and we can get to desktop and everything is fine in the new account. Is there a way to delete the old/corrupt login keychain from within the new account, or otherwise restore the original account? Naturally we did disk repair and permissions repair.