hardware volume
You must have speakers or a headset plugged into your computer to hear audio from a chat room.

- speakers
If you are using speakers be sure they are plugged in correctly and that the power is turned on.

Adjust the volume knob on the speakers to about 3/4 of the way to maximum.

- headset
If you are using a headset be sure that it is plugged into the computer correctly

Some headsets include a microphone, if this is the case there will be two plugs at the end of your headset cable

The plugs on most headset cords have an 'icon' of a microphone and/or a speaker on each plug

Be sure your speaker plug is plugged into the speaker output of your computer

Be sure your microphone is plugged into the microphone input of your computer

Some headsets have a volume control or mute button half way up the cord. If your headset has this feature be sure the volume control on the cord is turned up the whole way and that it is not on 'cut off' or 'mute' mode.

software volume
Enter a voice enabled chat room

You should be able to hear people speaking when a microphone icon appears to the left of their nickname

Adjust the output volume of the chat room by using the speaker slider in the 'audio toolbar'

Slide the control to the left to decrease the volume
Slide the control to the right to increase the volume