I would check the main earth strap is nice and tight, if it isn't they tend to try and get some earth through the ecu earth points when you operate the starter and fry the ecu.
If main earth is good, most likely a duff starter, or solenoid, does it run etc if you bump start it ?
Bridge the connectors on the solenoid, the two 13mm nuts and see if the starter spins, it won't spin the engine as not engaged, this will narrow down to the motor itself or the solenoid at fault.
If the starter has had a bad oil leak leaking oil in the starter it kills the carbon brushes and will smoke etc a lot and not turn over.
tabetha