Have you checked the CD player? Maybe it has a mute switch or a volume control that somehow got turned down.
Some CD players have inputs for signal from other sources (digital or analog), and they have a selector switch to choose between internal CD versus the external source(s). If your CD player has this, be sure the check the source selector.
Is there some way to verify that the CD player is working? Maybe you could plug it into another system (e.g., possibly an iPod) to see if it is functioning (a la Swampwalker's suggestion).
Some CD players have inputs for signal from other sources (digital or analog), and they have a selector switch to choose between internal CD versus the external source(s). If your CD player has this, be sure the check the source selector.
Is there some way to verify that the CD player is working? Maybe you could plug it into another system (e.g., possibly an iPod) to see if it is functioning (a la Swampwalker's suggestion).