Whenever I go to play a sound file on my PC (a Compaq Deskpro) the sound only comes out of the speaker and not the headphones. When the headphones are plugged in I hear a click, followed by a soft “kshh” sound, but the music itself comes through the speaker. Incidentally, the volume dial under the CD-ROM seems to have no effect on the volume level; it seems that I can only control the volume through whatever software I’m using.

When plugging your headphones into the computer, I am assuming that you are plugging them into the jack on the actual CD-ROM drive (because you have the speakers plugged in at the rear of the computer at the same time). This problem you describe, can occur if you have digital CD audio enabled in Windows. When this is enabled, the headphone jack on the CD-ROM drive is disabled. To check this, right-click on ‘My Computer’ on the desktop, click ‘Properties’ in the context menu that appears, and click on the ‘Device Manager’ tab. Expand the CD-ROM section, right-click on your CD-ROM device, and click ‘Properties’ from the context menu. In the window that appears, click the ‘Properties’ tab. See if ‘Enable digital CD audio for this CD-ROM device’ is checked because that will prevent the headphone jack on the CD-ROM drive from working. Make sure that this feature is not checked, so that you can use the headphone jack on your CD-ROM drive. Make sure you have the volume set low before plugging your headphones in! However, if this doesn’t work, the problem could be loose cabling inside the computer. Turn off and unplug the computer, then have a look inside to see if any cables to the CD drive seem to be loose. However, be careful not to change anything and don’t touch any static sensitive components. If this still doesn’t work, then you might have to try plugging the headphones directly into the speaker jack at the back of your computer. Before doing so, check the manuals that came with your sound card and headphones to make sure you can do this and that it won’t damage any equipment (as your headphones probably have an impedence of 32 ohms and most speakers are 4 to 8 ohms). In response to your second question, the volume dial on the CD drive only adjusts the volume for the headphone jack on the CD drive, not the speakers connected to a separate sound card.