Engine wont crank over

Checked the fuses, had a few bad ones so we replaced them. Put a new ignition switch, still wont do more than 'click'. The gauges go haywire and the lights come on but nothing else.

Then we bypassed the VATS, still no good. Now we are switching out the circuit board under the passenger side dash with the one from a parts car that only has body damage.

Already did that, it is good. And we have a battery charger and have already make sure it has a strong charge.

Forgot to add, we have to keep disconnecting the battery or the outside light stays on.

I was on the highway from a long trip and my check engine light came on and it went off for a minute then my car died. I lost throttle power and my car started over heating. I pulled over and I let it cool off and all my electronics work. It will turn over but wont start. I am trying to find a good place to start looking on what to fix?

I know. I forgot to mention that. When the battery is connected the headlights taillights and brakes lights all stay on even though it wont do more than click and even when we do not have the key in the ignition.

We have been working on it for the last two weekends. I think we might call it quits and drag it to the shop.

Another key as in a key code, or actual physical key? The car has an aftermarket radio and the only way to enter a new code is either with the original radio or a mechanic has to use some kind of special machine. As for physical key, I only have the one and it is in decent shape.

Ok from the begining of my problems. I had a 2000 engine put into my 99 camaro. Recently it started loosing power and stalling at an even idel and under even a small load. Then when I went to start it there was nothing no clicks, buzzes ect nothing. So I tried it again after hitting the fuse panel inside the car. The it started. Still stalling. This happed again and I did the same with the same results. Then later that day I started it and it ran for a little bit then died and the radio and bright light indicator on dash and the blinker lights remained on after turning car off. I got it home and charged the battery and tried it again and the same thing but this time before it died all the dials on the instrument panel went tallywacker. Where should I start?

Ok well my car will turn over and it has a full tank of gas but it wont seem to start. Any suggestions?