2nd gen PLEASE HELP!!!

ok, heres the deal, im working on a friend's 2000 neon base model automatic. they blew the old motor and got another one out of a wrecked 2000. we got the motor in and fired it up, it ran for a few seconds, died and then wouldnt start, but would crank over. now it wont crank over, he has gone thru 4 ecus and 2 harnesses. the wiring connector going into the headlight/turnsignal box on the steering column looks like it may be melted, i jus replaced the starter for him and it still wont crank over, i wound up pullin the fuel pump relay and the starter relay and i hear a clicking noise fromt he back of the car now, it didnt do that with the old starter. when the old starter was installed still it would make a loud buzzing under the hood when ever the battery was hooked back up, not ir doesnt do that, but still wont crank over, when the key is turned to start none of the lights dim at all, except the display on the radio shuts off. I NEED to get this car running asap. it is of utmost importance. please help....

Did they really blow the old engine or did it quit running and they assumed it was blown?
In that case the engine may have been fine but you have an electrical problem.
I wouldn't want to be you, it sounds like it might be better to get the money back for the engine, have the junk yard pick up the car and buy a $500 car that runs.