I was driving along at 25mph and my car died. The cop behind me said he heard a boom sound, and saw a bunch of white smoke out the tail pipes.

I didnt hear or see that stuff, but now the car wont start.

It cranks over with no odd sounds (I got it to slightly backfire in the manifold after cranking on it for about 10 seconds), the oil seems normal (no metal or foaming) , and the fluid in the radiator seems normal ( no discolor or foaming ). There are no leaks under the car , or on the engine. At first I thought it sounded like a head gasket problem....but after I saw the fluids were fine I am not so sure.

I live in an apt so I cant work on it here, and I dont have anyone to help me diagnose it (like in the sticky above) by bump starting it and checking the wires.

Before I have it towed to a shop , I wanted to have a clue as to what to tell them I think is wrong with it. Thanks for the help guys ---