An issue with audio playback on your computer is often a simple problem that takes only minimal effort to fix. Unfortunately, your problem might be more severe and might require you to purchase new hardware. There are many reasons why your computer's sound is not working, so troubleshooting this problem will take you a few minutes to check each of the possibilities.
Operating System Volume
Ensure that the volume is not muted in your operating system. Some laptops have a mute button that you may have accidentally bumped.
Plug a pair of headphones or speakers into the audio port on your laptop. If these work then your computer's sound card is working correctly, but there is a hardware issue with your laptop's speakers.
Reinstall the drivers for your sound card from the website of your sound card manufacturer. If your laptop has Windows installed, you can go to the support section on the website, enter your sound card model number and select the download from the search results. You can find your sound card model number by opening the Device Manager and clicking on the "Sound, video and game controllers" section. If you have an Apple laptop, you can navigate to the Apple Support website and download the drivers for your Apple computer.
Although this is not directly related to the sound card, sometimes restarting the computer can fix this type of sudden problem.