1990 Civic LX Sedan. Bone Stock dual-point D15B2.

So basically one day I came home from work, parked my car. Went back two hours later and it would turn over but not start. Has not started since. It has no spark at all. Power is getting to the dizzy (via the black/yellow wire) and we tried a full dizzy assembly (wires, cap, rotor, everything) off of a perfectly running car and it still does not get spark. According to a multimeter, the head is a perfectly fine ground. We also swapped the ecu off of the running car and still nothing. Any ideas?