What part of the system conversion in a situation like this presents the greatest risk?

It was 7 p.m. on the Friday heading into the Labor Day weekend 2006, and Steve Nelson, the newly appointed Chief Information Officer (CIO) for Gregg’s Appliances, Inc. (Gregg’s), was facing a deadline. Actually, he was facing two deadlines. First, Hewlett-Packard (HP), Gregg’s principal information technology vendor, had chosen to discontinue support for its line of HP 3000 mainframe processors, the operating system (MPE), and the proprietary database management system (Image) that Gregg’s relied upon for its transaction processing and inventory management applications. The last support date was December 31, 2006.