I really need some assistance- I hope someone can offer me some....

I have a 4 1/2 year old cat. I got him from a friend when he was about four
months old, because she could not handle him, with a baby coming and a two
year old. Anyway, since he has come to live with me, he has moved five times,
most recently this past Monday. We have always lived in apartments, and now
I have bought a house. He is the only cat in my house, and always has been.
Two apartments ago, I tried having a puppy, but that only lasted four days.

Anyway, since we have moved into this house, he has been pooping on the floor,
but peeing in his litter box. Initially, I had the litter box in the
basement, which is unfinished, with a furnace, hot water heater, washer,
dryer- a scary situation for a cat who has always lived on a one floor newer
apartment. So, I moved the litter box to the main floor bathroom, where his
litter box had always been, hoping this would help. That was yesterday.
This morning, I woke up to find poop on my carpet again.

Howie (my cat) has had problems with this in the past, but just occasionally.
He had been pooping on my couch in the past for other various reasons- after
other moves, after strangers would leave (he is somewhat of a fraidy cat when
people come over, but he is very affectionate towards me and other people he
knows and likes) but I put foil on the couch, and that seemed to help. But,
since Monday, he has consistently pooped on the floor, not pooping in the
litter box at all, something he has never done. I refuse to cover my entire
house in foil! A vet I contacted told me to lock him in a room with his
litter box and food, so I did, trying to keep the food away from the litter
box. Does any one have any suggestions? His constant crying and meowing are
making me feel so guilty! Thank you for any advice in advance....