In this paper we study the formal modelling and verification of a network player system using Duration Calculus, a real time interval temporal logic. The system is modelled by the conjunction of a number of Duration Calculus formulae each capturing a basic property of the system. That the system satisfies the requirement is expressed by the entailment of the requirement formula from the system formula. We use an automated tool DCValid for verification. DCValid is a model checking tool and it cannot verify our system in the general form, and therefore a special instance is derived from the general model and subsequently checked using DCValid.