You will need
  • Personal computer or laptop speaker system.
To start, restart the system unit. It is possible that the absence of sound caused by software failure, the operating system is returning to normal after a reboot. Check peripheral audio device, audio speakers, headphones. If they're connected to mains power and is connected properly to the system unit. Speakers are usually equipped with a separate power supply switch with volume control – check the controller. If you have another, working computer, check the function of the audio devices on it.
In that case, if external audio device is working and the sound still does not work, you must go to the test settings of your computer. If you have installed Windows operating system, look in the lower right corner of the monitor speaker symbol. Make sure that the symbol is not crossed. When you hover over the speaker icon and left clicking will display the image of the volume slider. Set the slider to the end position corresponding to maximum volume.
Check whether is no sound at all or only when playing media files. In the absence of sound check if the audio drivers for the system. To check hover your cursor on the icon "My computer", click "Properties" — "Hardware" — "device Manager" tab in the "Sound, video and game controllers". The presence of an exclamation mark points to the lack of necessary drivers. Download them from the official websites of manufacturers. If the audio playback device is turned on and functioning, but when you play a multimedia file there is no sound or picture, it is obvious that you have not installed the necessary playback codecs. It is possible to upload them also on the official websites of manufacturers of codec packs.
If the sound still does not appear, then probably the failure of security systems. If possible, make sure the audio card, with installing it on another computer. Modern faulty sound card replaced - if the card is broken, to restore functionality of the audio system will need to purchase a new one.
In that case, if the audio card is OK, you need to check for the presence of conflicting software. Reinstall the operating system to an earlier date, because it is not excluded that occurred the installation of any service routine or virus that is blocking the sound card. The restoration will remove this routine, it will become clear if this is the cause of the fault or not.
It should be noted that the reinstallation of the operating system is an extreme measure. In the absence of effect it is recommended to contact an authorized service center serving your computer, for qualified help.