in device manager the sound card is the audio controller
1. firstly try to find if mute all has been ticked
click start>all programs >accessories >entertainment >volume control and check that the mutes are not ticked.
2.or you can then right click my computer icon >manage >system info>device manager
find the sound card in the device listings
right click the audio controller and you get some menus to check
if there is a yellow ? then delete the sound device and reboot.
if nothing appears wrong you can try this:
3. The DirectX Diagnostic Tool is designed to help you troubleshoot DirectX-related issues.
The default installation folder for Dxdiag.exe for Microsoft Windows 2000 and Microsoft Windows XP is:
C:\Windows\System32
To start the DirectX Diagnostic Tool, click Start, click Run, type dxdiag in the Open box, and then click OK.
Sound
The Sound tab displays your current sound settings, and enables you to test DirectSound. The Sound tab can tell you if your audio driver is "Signed" - which indicates that it has passed Microsoft's Windows Hardware Quality Labs testing regimen.
The Hardware Sound Acceleration Level slider is used to correct audio glitches that might be caused by some audio drivers. Reducing the acceleration by one notch and re-testing the application is the best way to troubleshoot DirectSound audio problems. Lowering the Hardware Sound Acceleration Level from the default setting of "full acceleration" may disable advanced audio processing techniques, such as 3D spatialization from functioning.
If the DirectX Diagnostic Tool detects a problem with your sound settings, a warning message is displayed in the Notes box.