Once again, as pizzaguy said, what are the EXACT symptoms ?
[ ] turn key, dash lights up but engine does not turn over.
[ ] turn key, engine turns over but does not start. Do this three times, then nothing when key is turned. Disconnect battery, reconnect then same 3 strikes and you are out scenario.
[ ] engine starts, idles rough, sometimes stalls.

I believe you stated that the 'relay' was replaced. was this the 'Relay Control Module' ( RCM ) ?
Have you replaced the CPS ? ( Crankshaft Position Sensor )
Is this a manual or automatic transmission ?