If the sound is fine when you are using Windows Media Player, then it is not a driver problem. First thing you can do is to check the volume of your applications from Sound Mixer menu. Double-click the sound icon from your taskbar, check the sound level for different application, adjust the volume and see if it works. The second solution is to adjust the speaker volume to different channels. Go to Start, Control Panel, Sounds and Audio Devices, click on the Speaker Volume tab and adjust the settings. Finally, access Sounds and Audio Devices again, go to Sounds and reset your Windows sound scheme to Windows Default.