I have a 7 lb cocker/pomeranian mix who will NOT stop going to the bathroom on my carpet. She is 5 years old and been "trained" to go outside in her dogpen. She doesn't have a doggie door but we let her out often. Its gotten to the point where I let her out every hour and she won't go, then comes back in and goes on the carpet. I don't know how to discipline her or correct this behavior. Please help!

Don't just let her out, TAKE her out and wait till she does it! Tough on you, but which is the lesser of two evils? It's your choice!

If the smell is still there she will more then likely keep going there.
Maybe their is something wrong, is she maybe ill? A trip to the vet with a stool sample might be a good idea. Just to rule out any sickness.
Maybe try keeping her on lead with u in the house and redoing puppy traing all over again if she is well. Take her out when u know she has to go and give a lot of praise.
ttfn :)

If she's 5 years old and has been housetrained until recently, I would suspect a urinary tract infection - which is best diagnosed by a vet with a urine sample, it can be treated with antibiotics, and as long as there is no trace of urine left in the carpet/house then dog will often stop this behaviour

Whoops sorry I too ment urine sample.
ttfn :)