BMW Repair: starter, starter car, airflow

Question
car ran fine ,then it wont start all of a sudden,had battery fully charged and still wont start,help? 2001 bmwci vin.wbabs53451ju84870

Answer
Fuel.  Air.  Spark.  Timing.

Check these.  
Is your starter turning the engine?
Are you getting fuel to the injectors?
Any massive restrictions to the airflow? (not likely)
Are you getting spark at the cylinders?

If all of the above, then the timing is likely off. (Not likely)

Let me know what you have from above, and we can narrow it down.