I posted this in your old thread.
http://www.yorkietalk.com/forums/tra...-year-old.html
First, it sounds like marking to me. Neutering may or may not help this. Once it's already an established habit, it will be hard to break. But possible. I would suggest starting potty training ALL over again. Get a crate or an ex-pen and keep him contained when you cannot watch him 24/7. When you're home, take him outside (or on the pad, but personally I see more housetraining problems with pad trained dogs) every hour until he goes. Praise and treat like crazy when he goes where he's supposed to. When you leave the home, put him in a crate or pen. Dogs don't act out or do stuff to piss you off, they're not like humans in that sense, lol.
He sounds bored to me. How much exercise does he get? Some dogs need more exercise than others. Jackson gets like this when he has been confined in the house for too long, where he will start finding all the babies toys on the floor and decides to start running thru the house with them, lol. During the warmer weather (or when it's at LEAST 35 and above, for my sake) we go for at least 1 walk per day, minimum of 30 minutes, usually an hour walk. Weekends in the summer we try to walk 4 miles once a week. We also get to the dog park 1-3x per week and stay for 2 hours usually (this is more so in summer/spring). A tired dog is a happy dog!
He crashes hard after running around at the park or going for a walk. With these cold winter months we've had, we do a lot of trick training. I find it's a really great way to keep his mind occupied and working. Learning a new trick wears him out but he has so much fun doing it. Or we'll play a game of fetch indoors for 15 minutes.
Obedience training is always important to live a happy life with your dog. Teach him the "drop it" and "leave it" command. I find what works for us when Jackson has something in his mouth he's not supposed to... we trade. I give him something better (i.e. treat, other toy, etc) in return for what he had. Sit, stay, and down are always good basic rules to start with.
As for the cat, yelling at him no is not going to help because he doesn't understand what no means. Yelling at him, he thinks your just joining in on the fun! Teach him to accept the cat. They may never 100% get along but it's possible to make them tolerate each other. I would out the cat in a crate for a few minutes to start, and let your dog sniff, explore, etc. Whenever he's being calm around the cat, give him a treat and tell him good boy. Let him know that is how you want him to act around the cat. I find that having the cat and dog in a closed room with not any furniture that the cat can get under or on top of works better... the cat being hidden or out of reach usually drives the dog more crazy so just teach them to get along.
I hope this advice helps!