It is commonly believed that positive opinions of students and teachers on the possibilities entailed by computer use would increase the efficacy of computer-based educational processes. In turn, this amounts to postulate a relationship between measures of such opinions and well-defined patterns of interaction with computer-based educational tools. In this regard, this paper reports on an investigation performed in a primary school, designed to test whether expectations and opinions on computers, both of students and teachers, detected through suitable questionnaires, might be related to the effectiveness of computer use within a particular educational context. Our findings, contrarily to what expected, do not appear to support the hypothesis that a positive opinion on computers can lead per se to higher learning efficacy in a computer-based educational environment, as compared with a traditional educational setting