Make sure the disc is inserted correctly, with the label side up, and that the disc tray is firmly closed.
Make sure the underside of the disc is clean. If a disc begins to skip or freeze, or if there is no reaction whatsoever from a disc that has been inserted into the console, it might need to be cleaned. To clean the disc:
Note: Other materials, such as paper towels or a T-shirt, may scratch the disc. If there are any scratches, smudges, or fingerprints on the disc, it may not function properly.
Make sure the disc can be used with your PlayStation. Only PlayStation format software titles and audio CDs can be played on the PlayStation system.