This paper presents both the design and the pilot formative evaluation study of a computer-based problem-solving environment (named LECGO: Learning Environment for programming using C using Geometrical Objects) for the learning of computer programming using C by beginners. In its design, constructivist and social learning theories were taken into account. The general design has taken into consideration models of the learning process and subject matter as well as potential learner behaviour in dealing with fundamental tasks. The main emphasis has been placed on the role of: (a) multiple external representations in student learning, (b) motivation, through performing problem-solving activities taken from the familiar and meaningful context of drawing, using simple geometrical objects, (c) the active participation of students in their own learning by using hands-on experience, (d) appropriate feedback on the actions taken by students, to aid their self-correction, and (e) holistic, activity-based, multi-media, multi-representational and multi-layered content for the learning of basic concepts of programming using C. LECGO was pilot evaluated in the field through a qualitative and comparative study where nine 12th grade (18-year-old) students participated. In fact, students faced three similar yet not identical sets of four tasks across three learning environments, namely; paper and pencil (p-p), Turbo C and LECGO. The data emerging from this field evaluation study indicates that students gain better results within LECGO than in both the p-p environment and the typical programming environment of Turbo C, while performing similar activities. (Contains 4 tables and 4 figures.)