I had this problem around 6 or 7 years ago, and solved it then, but I can’t remember how. When I put audio CDs into either of my CD-ROM drives I can’t hear the music from my computer speakers (although the CD-Player program pops up, recognizes the cds, tells how long the tracks are, etc.) If I put headphones into the jacks on the cd-rom drives, I can hear the music. Any ideas why this is happening?
Sometimes CD-ROM drives need to be connected to the sound card with a small cable.
RealityChuck is probably right–if you have a manual for your CD-ROM player, look up “Red Book Audio” for instructions on how to hook up the cable.
It’s also possible you accidentally turned off CD audio on your soundcard mixer. Look in the bottom right corner of your screen, near the time display. If you see a little speaker icon down there, double-click on that. Then check to see if your CD Audio volume is turned up and not muted.
Do you have a vid capture/tuner card?
Mine (Diamond DTV2000) has a menu control that must be set for “tuner” or “CD” input. If set to “tuner” it will cause the symptom in the OP.
Some sound cards have their own volume control on the back of the card (the part of the card that’s exposed with all the inputs on it). The volume may be turned all the way down.