I reversed my polarities on my battery for about 30 seconds and have done some damage. I replaced thealternator. the solenoid is also gone as it won't engage but starter wil turn on connecting. Car won't start by key. I have adead short somewhere. help

dude, why did you do that??????

You probably have more than a short. Check ALL the fuses and fusible links. There is still the possibility that you cooked many of the solid state components like the ECU, ignition control, distributor, ABS, climate control, gauge cluster, etc.