car stalled as I was leaving parking lot will not restart

If a repair shop told you didn't have compression in a cylinder and needed an ECM they are either brain dead or blowing smoke up your ***! Compression in cylinders is mechanical issue only and ECM is electrical. "no compression" would mean total failure of piston and you have scrap metal for a motor and would have sounded like a wrench got jammed in your motor right before the abrupt halt to your journey! That being said it leaves the other two components to an engine running, which are gas and electrical. I have no idea how knowledgeable you are so I assume none just to be sure not to overlook the simple things. Process of elimination is the best way i know of for me. You said no spark but just in case you just meant wont start an easy check is to start with is take off one plug wire and lay it next to a solid metal spot close so that a spark can jump from the plug to the metal. This is best done at night in as dark a spot as you can. Have someone turn key as if starting car while you watch the plug. If a spark happens then its gas or timing issue. If no spark then it gets more complicated and its a matter of checking parts for the reason. To check if its gas get some starter fluid and spray some in through air intake and try to start it and if it starts then dies its gas problem of some sort. If a spark happens in a cylinder with gas in it at right time there will be some action! Those are my suggestions for a starting point for what they are worth. Good luck and let me know what happens or update if its fixed already.