The problem may be caused by improper audio setting, the following procedures are used to check the setting of Recording Control:
1) Click [Start] -> [Programs] -> [Accessories] -> [Entertainment] -> [Volume Control].
2) In he [Volume Control] window, click [Options] and select the [Properties].
3) Choose [Recording] under the [Adjust volume for].
4) Make sure that box of [Line], [Microphone], or [CD Audio] were checked and click [OK] button.
5) In the [Recoding Control] window, checked the [Select] box accordingly to enable the device to record sound. The volume can be adjusted by scrolling the scroll bar.
6) Close the [Recording Control] by clicking [Options] and select [Exit].