Q When I plug my headphones into the socket on my PC's CD drive I can only hear the CD, not the sounds from the PC such as gameplay. Why?

A Your PC's CD drive is capable of reading two types of data. The first is normal CD audio, just like your hi-fi system. That's what you can hear out of the driveÆs headphone socket, and nothing else. In fact, if you could power the drive while the PC was turned off, it would still work as an audio CD player. The other sort of data is PC data, and that might be video, sound clips, a game or whatever. Any sound that comes in PC data format (and sound created by programs run on the PC) is produced on your PC's sound card, and fed out to speakers or headphones via the socket on the sound card. Assuming your CD drive is installed correctly, the CD audio will also be fed to the sound card and mixed with all other PC sounds.