This is a study of how use of computer artefacts could be understood from the aspect of trust. Meanings of trust are discussed and rather than to understand trust as a possible solution to problems of uncertainty and control, trust is here seen as a fundamental aspect of life, including experiences of knowledge, certainty and control. Computer artefacts are often talked about as tools. It is argued that the ‘tool metaphor’, by leading to a narrow understanding of social consequences of computer use, conceals questions of power and dissolves questions of trust, and thereby increases possibilities to exercise power. As a contrast to the tool metaphor, a perspective on computer artefacts as externalisations and computerisation as ordering is presented, and it is discussed how computerisation, as well as other kinds of ordering changes needs and conditions for building and grounding trust between people.