You are watching a movie or listening to music and suddenly the audio goes off and there is no sound. This sound issue happens mostly in Windows 10 and to fix sudden no sound in Windows 10 while listening to a Mp3 file using the Windows Media Player or watching a movie using any video player, do as follows:
1. Make sure the Audio Driver is installed and updated (Right click on the start button >> Device Manager >> Audio inputs and outputs)
2. Make sure the correct playback device has been chosen (Right click on the volume button in the taskbar >> Playback devices)
3. Assuming you have already done thee 2 steps and still you have the Sudden No Sound issue, go to step 4.
4. Click on the Start button and start typing this command: services.msc (if you have disabled Cortana, you still can type in the Start menu)
5. On the Services menu, find the Windows Audio and click on it
6. From the left panel, click the Restart and wait for the process to finish
7. Now the Sound should be back