How to Fix the Sound in Windows 7

Check Your Volume
1. Click 'Start' and then open the 'Control Panel' window. Click on 'Hardware and Sound' and select 'Adjust System Volume.'
2. Check that muting is not turned on. If the 'Mute' button has a red mark on it, click the button to turn muting off.
3. Move the volume slider up to increase your computer's system volume.
Check Your Cables
4. Verify that your speakers are plugged into a power source and turned on.
5. Check that your speakers are plugged into the line-out jack on your computer. The line-out jack is usually a lime green color.
6. Close all audio applications and then unplug any USB audio devices. Reconnect the USB audio devices, and then re-open the audio application.
Check Your Sound Card
7. Click 'Start' and then open the 'Control Panel.' Go to 'System and Security' and select 'Device Manager.' Expand the 'Sound, video and game controllers' subheading and locate the sound card under this category.
8. Right click the sound card and select 'Properties'. Select the 'General' tab and check the device status to see if there are any noted problems with your sound card. If there are problems listed in this section, or there is a yellow question mark shown next to the card in the Device Manager, you need to reinstall the device driver.
9. Go to the sound card manufacturer's website. Download and install the latest driver for your sound card. Don't use the driver that came on an installation disc as this version may be outdated.