Rep Power: 0

I have a 2004 civic. I just bought the car a couple of days ago. I decided to see about putting in a sound system. The car was already pre wired. All that was needed was a power cable. I ran the power cable from the battery to the trunk. The car had a amplifier and subwoofer already in the back but the power cord want connected and the power cord looked very old. So I removed that cord and put a new one. When i turned the key to the on position everything was fine however the systemthat came with the car wasn't working as well as it should like volume was coming from the speaker but no bass. So i removed that just by unhooking the cables. I took the system i put in the 96 civic and just transferred to the new civic by just hooking the cables to it. Once again when I turned the key to the on position everything was fine. But when I tried starting it Did nothing. Do it seemed like the battery may have died from the extra power that the amplifier was drawing in. So I jumped the new civic with jumper cables and it started. I turned the car off and back at not starting again. So i bought a new battery from advanced auto. I put the new battery in and went to start the car and no lights or anything is working except for the vent fan was blowing. I tried starting the car and it wants to start but just not turning over.

 
Rep Power: 243

 
Rep Power: 0

I disconnected the power from the amp. Still nothing.

 
Rep Power: 228

Might have blown your main fuse for the car. Were you running a safety fuse on the amp V+ cable?