Honda Civic just stopped running
Haven't given anyone much to go on here. You have to start with some good old fashioned troubleshooting. Is the engine turning over (cranking)? If Yes, the battery and starter are good. Does it have spark? Pull a plug wire and test. If not, you have an ignition system problem. Does it have fuel? Starting fluid is the easiest way to check (remove air filter and spray a bit in to see if it starts). Does it have timing or compression? Could be a broken timing belt.
It may be a bad alternator , get it started and test batt, for 14+ volts , an idiot light should come up but not always