Car just eall of a sudden will not fire and run but turns over fine.

I have had this car about 3mths and in that time have had no issues at all with the car. It has run flawlessly and cranked up on the same timing mark every time. I know the very basics about vehicle mechanics but have never owned a German auto and all that I know is their expensive to get repaired! "This scares me because my life is hanging by the the thread of dependable transportation."
Two days ago when attempting to leave my house, the car all of a sudden just decided not to crank and just kept turning over without even a spudder. Then minutes later after trying over and over to crank it, it all of a sudden cranked up and I drove away hoping to never be bothered with it again; "knowing that would have been virtually impossible!" Anyway, it's 2days later this evening when, again leaving my house, it decides not to crank and there is not even a sound accept the engine turning over via the starter motor.
There have yet to be any indicator lights of any kind. There is though, a security system called a viper transponder that is inactive in the car. I know some of these models have options to shut down the operation for whatever reason. From what I can tell, the system has been disconnected though.
Wondering if there may be ANY common issues to occur with this make / model for these type symptoms. Or? "Do older bmw's blow fuses for their computers or whatever else? I have not a clue accept I feel abused not having any idea of what im dealing with. ANY IDEAS OF WHERE TO START?. Please and thank youuuu