sorry but can you be more specifics....i mean your mac had a random shutdown or what else ???....I've had this machine for a while, and when idle instead of just logging out it'll reboot sometimes. I really have no idea what to check or what to do, any suggestions are helpful, if you need any more information let me know.
ok ic....but have you check your hardware manually , or something trouble has been damage your machine , for examples , you ever using your mac for along time , it can make your machine overheat , and then the machine isn't working properly .....or maybe you should re install your mac using mac os x ,When i leave my MBP on and walk away, it will reboot itself. It's setup to only send me back to the login screen once it's been idle but it physically reboots. I don't know how i can be more specific then that.