Need help! Dog peeing in house.

[Rory_W]

Our dog is 17 months old and for most part was house broken. We had her spayed a month ago and now she pee's in the house in various places. Vet say she is OK medically speaking. We have not really had any changes in the home lately. She has use of a dog door and uses it most of the time, though she sometimes does not make out of the garage. Wife has found pee spot and we also get poop on carpet, but rarely. We never catch her and when we do she is punished. She know she is in trouble when we find it and hide under bed. Any help would be appreciated.