We present comparisons of theoretical and simulation results for static and dynamical correlation functions for a very simple model of attractive colloidal systems, the short-ranged square-well potential. In the region of the phase diagram investigated, the system displays slow (glassy) dynamics. In particular, we compare the static structure factor calculated by Percus-Yevick closure versus the simulation results, both in the small-and large-wavevector ranges. For the same model, we also compare the non-ergodicity parameter, i.e. the long-time limit of the dynamical density correlators, as calculated by mode-coupling theory and by simulation, confirming the presence of two distinct glassy phases.