I've also lost 40 pounds with purely calorie counting. Although I've managed to keep it off for two years, and I don't see it coming back (easily). My approach was to kill bad habits one at a time and create new good habits to take their place. For example I replaced smoking with walking. I replaced high calorie snacks at home with fruits and vegetables so I would go for those instead.

The key has been to take things slowly and not try to do too much at once. I still count calories, but what I eat is pretty much a mindless habit now, (the good kind). I have also gotten into the habit of weighing myself daily and plotting it on a graph. This gives me very good feedback when I'm going in the wrong direction.

Almost 4 years ago I weighed 220 and smoked a pack a day. Now I weigh 175, ran my first 5K this year and I ride my bike 20 miles to work every day!

Edit: I hope you give it a go again. It's not easy, but once you turn the corner it's really worth it.