PCDRA was designed to provide the average biologist with a user-friendly molecular display on a low-cost personal computer. The package is menu driven and is built so that a biologist, with little or no computing knowledge, finds it easy to use. The system gives a color representation with depth cueing of a protein whose atomic coordinates are stored as a PDB file. Moreover, the system presents several features similar to HYDRA and therefore is a good introduction to molecular graphics, especially for beginners in protein modeling.