'93 240sx Se , need help asap. Electrical problem.

[Skylinerz]

I'm kinda of a noobie in here...please be gentle...

Well, my battery died. When I went to hook up the jump cable, I put the negative in the positive and positive in the negative[/B]. for like a few seconds, I get a spark lid up like fire with a little smoke. After that I went to turn on my car but there were no dash lights on nor any turn signal/emergency, no break lights, no sound of fuel pump...basically nothing... I checked all the fuse they seem to be okay except for one, but I replaced that, but other than that..engine fuse and dash fuses are ok. Still not sure if the relays are ok, but I heard that they are very hard to get burn. So I don't know why am I still not getting any power...Could it be because I gave my ecu a shot?...if I smoked my ecu, would the '95 240sx ecu interchangable?...Please help..I don't know what's going on now...

I have a '93 240sx SE

Thanks in advance.