'88 Supra Not Starting
 

I accidently connected the negative wire to the positive on the battery and vis versa. and there was a spark. Then when i went to correct the problem by placing the plugs on the right = and -. The engine starts, then just turns off. There is a loud constant beep. I cant figure out what is going on here.

P.S. before I accidently wired the battery wrong the engine would of course start just fine.