Car Problems PLEASE HELP!!!!?

I bought my girlfriend a new car for her battery and she hooked up the terminals wrong. She said there was a pop. Now the car wont get any power. I took the battery to be tested and they said it was perfectly fine. I personally hooked up the car battery correctly and now theres no power. The radio wont even turn on NOTHING! I also checked all the fuses under the hood and in the car and they all seem to be fine. Does anyone else know what it could be? It's an 89 honda civic any help please!!