So you had the head machined & replaced the head gasket then reinstalled everything but it wont start?
Please clearly provide more details, such as...
- What year, trim & tranny Civic is this?
- What engine is in it?
- Did you double check all the connections and grounds?
- Is the gauge cluster lighting up?
- Does the car at least turn over?
- Did you disconnect the batery before removing anything? If not then its possible you may have shorted out the main relay somehow, I believe.