David Cooper purchased a computer and software for his supermarket business. He was using a soft- ware program recommended and installed by the seller, Contemporary Computer Systems, Inc. The sales contract had a clause that stated that no refunds would be given after the 90-day warranty period. Cooper initially had problems with both the hardware and the software. Contemporary Computer Systems tried to remedy these problems. A pattern of problems and attempts to fix them went on for some time, far beyond the 90-day period expressly described in the contract. When Cooper had had enough, he decided to revoke the contract and demand his money back. Contemporary Computer Systems said the 90-day express clause in the contract precluded this action. Who won?