try not jumping it at the battery,
the battery plates could be so sulfated that they let NOTHING through.
alot of cars have another spot you can put the positive cable. and then the neg on the shock tower or something
its also possible its not a battery?
it might not be a charge issue could be more to our problem here.
If at all possible replace the battery. if its more then a few years old replace it, its good insurance.
if new battery + trying to start car = still dead.
you might have a starter that took a dump. one way to "try" and get it started is have someone hold the key in the start poss. and tap the starter GENTLY with a hammer. try and get it to kick over. obviously be sure your in a safe spot as the veh might start while your under it.