Please Help

Hi! I'm new to this board, and I really need your help. I am mom to a 3-1/2 year old, long hair, male (neutered), indoor only tabby. (Good grief, is that a mouth full or what?) His name is Jigga. Anyway, for the past 2-3 weeks, he's taken to defecating on the carpet. It's not runny or anything to indicate that he might have diarrhea and is unable to make it to the litter box. And, he's not just centralizing it to one location. He seems to do it where ever he happens to be when the urge hits him. We scoop or change the litter box daily. (I'm a firm believer that no one should know we have cats until they see them.) I haven't changed litter brands (loyal user of Fresh Step for 3 years), and there's been no change in his diet. I took him to the vet who suggested that maybe the other cat (a male short hair gray tabby)(his name is Shawshank), did something to upset, frighten, or otherwise disturb him when he was in the litter box taking care of business. She suggested that we get another litter box and confine Jigga to a specific area with that box to re-introduce him to the litter box. We're to do this for about a week; especially when we aren't at home. We've been doing this for 2 days, and he's fine when he's locked away. But, in the evening when we release him for awhile, he's still having accidents.

Has anyone else had this problem or anything similar to it? If so, what did you do to take care of it? What was the cause of it?

Any info/advice you can offer will be greatly appreciated.

Thank you,

Lisa