Will do anything to fix problem!!!!!!

ok, heres my problem, i have a 1999 honda accord EX sedan, vtech, 2.3 4 cylinder car, i was putting on ne headers today and didnt really do anything with the power, now for some reason every time i connect the battery the 100amp main fuse blows, all the other fuses are ok, like i can use the emergancy lights and the horn but nothing else, i am very desperate for a fix, its about 4 am here and i am still trying to find an answer........ PLEASE, if anyone can help, i need it.....

you need to trace wiring from main fuse location to se if anything touches car's body, it most likely be one of big wires is grounded. i would look closely at starter and alternator wires.