There are many studies in Information Systems on the adoption of new innovations. This paper, on the other hand, presents the findings of an empirical study, which explores factors affecting the adoption of upgrading software. End users? perception of former products significantly affects their adoption of the upgrading products and thus, their behavior changes accordingly. We use Windows operating systems as an example. Most people have been using Windows operating systems. They are familiar with the current software. Although Microsoft has enhanced the capabilities of new Windows operating systems, these new features are sometimes more than necessary. Thus, what factors drive the users to upgrade? A survey is carried out in a university and a government department. 300 data points from microcomputer users are collected. Five hypotheses are formulated to test research concepts from Marketing and Information Systems. From the marketer?s point of view, our findings indicate that adopters of upgrade software are stronger in opinion leadership and more independent when making purchase decisions. They also prefer seeking novel product information by their own effort. We have borrowed two innovation acceptance factors, perceived ease of use and perceived usefulness, from the technology acceptance model in Information Systems. We find that upgraders and non-upgraders have different perceptions of ease of use and usefulness in the older software versions. Furthermore, software usefulness is more significant and crucial to urge the users to buy new version products than software ease of use. Implications of our findings, from both a researcher?s and a practitioner?s perspectives, are discussed.