Control Panel
Sometimes the computer does not have sound because the drivers to the sound card become uninstalled. You can check to see if there is anything missing by opening the Control Panel. This is found by clicking the start button and locating the control panel option in the right hand column.
System choice inside of control panel
The list of contents inside the control panel are in alphabetical order. Click on "System." When inside of "System" click the "Hardware" tab and then click the "Device Manager" button.
Sound choice example
Next to sound, make sure there are no yellow exclamation points with triangles inside. If there are, it means the sound card needs to be reinstalled or it is not recognized. Take the disc out that came with the sound card or download drivers from the Internet to restore functioning in your sound card. If there are no yellow exclamations, go to the next step.
Windows Volume Control
Check to see if the mute button either on the keyboard or in on the Windows Taskbar in the lower right corner has been accidentally selected. You can double-click on Windows Volume Control (looks like a black ball) in the lower right corner to expand it fully. If you discover a choice has been muted, uncheck the box and shrink it back down to the Taskbar. If there is no sound icon in the Taskbar, chances are the sound needs to be reinstalled. Use your CD or download the drivers from the manufacturer's website.