If you've stopped hearing sound from your computer, then you may need to restore the sound system
No matter how well you take care of your computer, it's inevitable that you'll experience a failure on it at some point. One of the most common failures is a sound system that does not work. If you've noticed that your computer's sound functionality no longer works, you may be looking to restore the sound system on your computer. Fortunately, by using a few different methods, you'll be able to do this.
Instructions Settings > Control Panel" in XP or "Start > Control Panel" in Vista/7.
5. Click "System and Maintenance > Device Manager" in Vista/7 or double-click "Device Manager" in XP.
6. Scroll down and click the "Sound, video and game controllers" icon. Right-click "High Definition Audio Device" and select "Update Driver Software."
7. Click "Yes" when asked if you'd like to update the software. Wait for the process to complete and then restart your computer. Your sound system will then be restored.
Tags: your computer, sound system, Control Panel, Device Manager, restore sound