No one can help you. "Now it won't start" is a meaningless statement.

Does the starter engage or not? If not, leave key at "ON" for 30 seconds, does the engine fan run fast? If so, replace or repair the RCM. If fan does not run fast and starter will not engage, we have more work to do to diagnose the car.
IF the starter engages and engine wont start, we also have more work to do (that is, more questions to ask) to diagnose the car.

GIve us a direction: Tell us if the starter is engaging or not.