Ok you need spark, fuel, and compression for an engine to run. I dont think you all of a sudden lost enough compression to completely kill the engine so you need to figure out what you're missing. Spray some carb cleaner into a vacuum port on the intake manifold and try to start it. If it trys to start or starts and cuts off, you have a fuel problem. If it has no effect, check for spark. Just pull a wire off of a spark plug hold the end of it very close to a ground. Have someone crank it and if it has ignition, it will spark to the ground (make sure to keep the end of the wire close to a grounding point or it will shock the #$%@ out of you). That should be the beginning to your diagnosis. When you get to that point post your results. Good luck.