Jump starting error...99 Pathfinder

Could use some input here....here's the deal....wife calls me up last night after work saying her Pathfinder has a dead battery...I knew the battery was on its way out, its the OEM and its a 1999...
So I grab a new battery at Napa on head up to swap em out this morning...Tit job... well I swap em out and notice I dont even get a spark when I connect that Neg ??? I'm thinking this aint good....Go inside and I have nada for lights or horn??
Try using cables still nada W.T.F. ???

So my wifes say the thing was dragging like a dead battery does...she heads down to the hospital and a security guys says hey I'll jump it...My wife says he hooks up the jump pack and sparks are flying bigtime and the truck is flat azz dead now....nothing...The dude says..that thing must be really dead I cant help you...

Well I would say a Fusable link or fuse has blown?? I hav AAA towing home...
Any buddy got any thoughts?? I'm hoping the computer didnt fry....

Thanks guys....
I found a 100amp battery fuse located in the center of the distribution box blown....took 2 freaking hours to get that mother out.....$1.83 later I was back in business...Jumped in and all the lights were on, a good sign....hit the key and it fired for a split second and now all it does is crank....


What a freakin drag...nevermind its damn near 0 outside....Something else took a dump with it....Its like it had a tad worth of fuel and fired for that moment and thats all she wrote....W.T.F. !!!!
Time for trouble shooting madness...damn I hate that chit....

Any thoughts are welcome...

Ya I'm thinking It should be a fun day of testing chit....bought the only thing I don't have is a noid light...Gonna take a run downtown and try to scam one....

Im just hoping the surge didn't get to the puter.... ..that would suck..

My wife said she was outside and watched the guy hook the booster up and then sparks flew bigtime.... Damn rookies !!!!

Got it running...

Check this B.S....I tested spark...has it....throw some starting fluid at it...she starts...check fuel pump...she works.....check fuel at the rail...has it......check ignition fusible links....both are good....test injectors....not working...no power...

So now I figure its gonna get funky....I was looking thru the wiring schematics following the injector wiring to see where they got power from.....ECCS relay,hmm..so I go to the main box and find it....low and behold its a 7.5 amp fuse...wait a minute...its missing???? W.T.F.??? I read over the cover and find the 7.5 in the wrong location....??

I remember when the AAA guy came...he said mind if I take a look at the main fuse box....Go right ahead I said...He pulls one (it's a 7.5 cause I remember the color) and says it fine...Whatever...I thought nothing of it...

Well him leaving the ECCS fuse open was my issue...As soon as I changed the mofo 100 amp yesterday it should have jumped right to life...IF the freakin fuse was back in place...

Oh well, live and learn...