Car shuts off while driving ? And OBD help .

What is your question?

It start up fine, but after driving for about 30 muints sometimes it shuts off with no warning or check engine light on, all I have to to is turn the key off and start it back again, how to diagnose it? What is the reason make it shuts off like that? - since there is no check engine light on, is there is any way I can get the engine performance, faults, error. Etc history from the computer? I heard that the computer restore all the data. - im in the market for OBD scan tool, looking for something help diagnose, live data, performance, . Etc, not just give me a code when the check engine light is on, any recommendations?