To restore the sound to your computer, a methodical approach and patience is required. Causes for the loss of sound for onboard or external speakers run the gamut from something as simple as a muted volume control, loose power cords or cables, to newly installed software, outdated sound card drivers or a disabled audio device.
Check Volume Setting
Left-click the speaker icon located in the system tray to launch the volume control. Move the volume control up to increase the sound output from the speakers.
Click anywhere on the screen away from the volume control to return it to the system tray.
Check the sound output. If you hear sound, stop here.
Speaker Power and Connections
Check the outlet to make sure the speaker system is plugged in and has power. Check the power strip/surge protector on/off switch.
Follow the speaker cables to the computer to ensure all are connected properly. Check the sound output. If sound is heard, stop here.
Disconnect the external speakers, and reconnect them to another computer. Check the sound output. If the speakers work, return them to the original PC and move onto the next section.
Enable the Audio Device
Right-click the speaker icon located in the system tray. Select "Playback Devices"; a list of audio devices appears.
Right-click in the empty space below, click "Show Disabled Devices" to reveal any hidden equipment. Right-click the first device, choose test and listen for sound. If sound plays, right-click this device again, and choose "Set as Default Device".
Click "Apply" then "OK". If sound does not play, move onto the next device and repeat steps until the correct device is found. Check the sound output. If sound is heard, stop here.
Update the Drivers
Log in as Administrator to update the sound card drivers. Click the "Start button" and then type "devmgmt.msc" into the "Start Search" box to open the "Device Manager".
Click the "+" sign next to "Sound, video and game controllers" to view the audio devices available. Right-click the audio device, then chose the "Driver" tab.
Click "Update Driver Software", and the "Hardware Update Wizard" appears. Choose "Install the software automatically", and click "Next". The Wizard searches the web for updated drivers, and if available, installs the new software. Click "finish" when the Wizard is done. Check the sound output.
Log in as Administrator and type "Restore" in the "Start Search" box to open the "System Restore" dialogue box. Click "Next" and choose a restore point closest to the last time the sound worked.
Click "Next", confirm the restore point chosen by clicking "Finish", and the PC begins the process of restoring the computer. The computer reboots when the restore function is complete.
Log in and check the sound output.
Sound Lost When Playing MMORPGs (Massively Multiplayer Online Role-playing Games)
Right-click the speaker icon located in the system tray. Select "Recording Devices"; a list of devices appears.
Right-click in the empty space below, click "Show Disabled Devices". Right-click any new devices, and then click "Enable".
Check the sound output. If sound is heard, stop here. If not, proceed to the "Update the Drivers" section.