I just received a dog from a friend who did not walk the dog and let her pee and poop all over her house. I thought that just walking her twice a day would solve the potty problem but I've found that right after we have walked her she will poop in the house. We have limited her diet to dog food once a day, because she was eating table food at her old house. How can I potty train her after two years of bad habits? She is an adorable dog, but we are losing patience with all the mess.