Look down at the lower right corner of the screen for an icon that looks like a sound speaker.
Click it once and a small volume control will appear. Look for the checkbox at the bottom of the control that says "Mute."
If it is checked, uncheck it.
Supply more information about your computer if this did not fix it.
August 9, 2010 10:04:06 AM
Double click on the same icon and make sure your WAV is not turned down as well, it is located first to the right of the volume bar. Also are you running a HI-Fi sound card? Sometimes this can conflict with the onboard sound on your motherboard.
Hope that helps.