This one is driving me nuts. I have a client who bought the machine this way- he clicks on the icon at start up, and it would log him into the desktop. He never knew the password. It sounds like this is how the previous owner set it up, however I am baffled. It is now not going to the desktop, but flashing white, and back to the log in screen. I have run all ASDs and EFIs, TechTools, DiskWarrior, etc. There were some software issues that were fixed and nothing it found hardware being an issue. I tried after all that, and still same issue. Any help?! Thanks guys.