after replacing my battery... Lol... [crying]

I have probably replaced 40-50 batteries in my life without a hitch. After I got done this morning, no power. Not even a dome light. Btw, the battery weighs 58.5 lbs and sits conveniently under the front passenger seat - an incredibly uncomfortable place to work. I thought maybe the battery was defective, so I switched back to the old battery. Nothing. Not a flicker.

The only thing I can think of is some type of master fuse blew. I just don't know which it would be. It would be something in the order of 100 amps would be my guess, but I didn't find anything helpful Googling. I would complain about how life sucks, but a lot of people out there dealing with far worse.