Help!! A wiring conundrum

[BabyBlue]

So, I was working on my blazer this weekend...installing my Sanderson Headers and after I finished installing the truck wouldn't start. Odd, I switched out my regular battery with my Optima...and still nothing. I checked the charge on both batteries and the Optima was fully charged and my other Battery was close to full capacity. Soooo, I decided to a look in the engine compartment...traced my positive and negative cables, which were both hooked up in the correct places since I never touched them. I reconnected the O2 sensor just in case it has some weird/out-of-this-world thing to do with it. Then I reconnected the headlight wires and everything else there. Tried again from here and nothing.

I then went to the interior because I had recently pulled the radio and cut a couple wires down there, thinking maybe I cut something I wasn't suppose to. Well, I no kidding couldn't find anything besides more hatred for the people that put this thing together in the first place. I followed my pink wire and my pink and black wires to the ignition and the fuse boxes with nothing noted. I pulled the radio fuse and decided to play musical fuses while testing the key to see if I heard the electric fuel pump start...and still nothing....

I have absolutely no clue as to what could cause this and I would rather ask to see if someone on the board might now before I start ripping into this thing anymore and end up with a pile of parts and still no answers.

Hope some of you guru's out there can help.