AWave and MIDI files are played by the sound card in your computer. Audio CDs are played by the CD-ROM drive itself in the same way that a regular audio CD player in a stereo system would play them. To allow the sound from the CD to come out of the speakers that are plugged into the sound card there should be a cable running from the CD-ROM drive to the sound card. Most likely when the new sound card was installed this cable was not connected or was connected incorrectly.
The first thing to do is to check that the CD-ROM drive is correctly playing audio CDs. The drive will do this completely independently of the sound card. Play an audio CD and plug speakers or headphones into the socket that most CD-ROM drives have in the front. When you play the audio CD using the software you normally use, you should hear the CD playing through the socket. (As an aside, CD-ROM drives will run completely independently of the computer, all they need is power). Most CD-ROM Drives have Play and Stop buttons on the front. You can press the Play button and hear music through the socket on the drive even during system startup.
If your CD-ROM drive works, all you have to do now is reconnect it to your sound card. Check to see if there is a small cable running from the CD-ROM drive to the sound card. On some computers, there may also be a 2- or 4-wire cable running from the motherboard to the sound card. This is used to redirect PC-speaker output to the speakers plugged into the sound card.
If there is no cable then you will need to get one from your local computer store. If you have a cable but it is not connected, then you need just to reconnect it. The third alternative is that is plugged in incorrectly. On the sound card in my computer -- an ESS 1868 -- there are several identical-looking 4-pin connectors. Consulting your sound card and CD-ROM drive manuals may help, but you may need to try each one and see if it works.
- Roy Chambers