Why my 1985 Cadillac Deville crank but can't start

Last autumn my cady run perfectly. Then I didn’t drive it much during the winter (Nov – Apr), maybe only total less than 50 kms. In may it started have difficulty to start, but when I used spray fluid, it started right away. But last week it totally died. It crank, crank, but wouldn’t start, even when I used spray fluid. I had it towed to a garage, they inspected it and said there was fuel, but no fire. They changed a distributor, still not working. They say still no fire.
Can anybody tell me what could be the problem?