Sometimes a CD player will display a "No Disc" error. What this means is that the CD player, for some reason, does not recognize the disc. There are various reasons for this error, from the CD lens eye being dirty to a CD format that is incompatible with the player. Troubleshoot through process of elimination.
Use a format that the CD player recognizes. For example, you cannot play the DVD disc format in a CD player. Also, some CD players won't recognize some burned CD-R/CD-RW discs. If this is not the issue, you will have to clean the laser eye of the CD player.
Drench a cotton swab with isopropyl alcohol.
Angle the cotton swab so it can reach the CD player's laser eye. Gently wipe the surface of the laser eye with the swab.
Blot the laser eye with the dry end of the cotton swab until the alcohol residue is gone. If this does not work, you will have to use a laser eye kit.
Insert the CD lens cleaner disc into the CD player.
Press the "Play" button on the CD player to initiate the cleaning process. The CD cleaner disc will stop when the process is complete. Remove the disc when it finishes cleaning.