re: Dog training question

There's really no point in punishing one for taking a crap in the house, unless you catch him in the middle of the act.

Is he going in the same spot?

I always confine mine to the room I am in, close doors, barriers etc. Dogs won't crap in their "den", however the den needs to be sort of small, this is why keeping one in a kennel/crate is the best way to house train one.

Marking will never end.

I also suggest feeding once or twice a day, then going outside for 30 minutes or until dog poops, after eating.