I agree with Gemy a vet check is in order, I'm wondering if he might have diabetes, and it sounds like his vision could be bad, dogs often get cataracts from the diabetes and this makes their vision poor. They see things more as shadows and this could be why he’s barking at the cat when he never use to. Diabetes also increases thirst and so urination is more frequent, perhaps this might cause soiling of carpet? Anyway, I hope the vet can find some answers. Regarding barking, I had a lot of success with Teresa Ford's thread on barking.
http://www.yorkietalk.com/forums/gen...h-barking.html. I trained every day for two weeks and I could see a difference by the second week. It's not as immediate as punishments such as coins in the can, but it's long lasting. Sorry you're so frustrated.