It is possible that sound is not playing when you try to play videos due to a variety of potential causes. To help troubleshoot the issue, I suggest checking the following areas:
1. Check your audio settings and ensure the volume level is turned up and the device's mute option isn't enabled.
2. Ensure that the video file or streaming service you're using has sound by playing it on a different device or platform if available, such as another computer or tablet.
3. Make sure any external speakers are properly connected and powered on if applicable.
4. Try restarting your device or browser to see if this resolves any software conflicts causing issues with your audio playback capabilities.
5. If none of these steps work, then it may be necessary to update or reinstall drivers related to your audio hardware components in order for them to function properly with current versions of software installed on your system (e..g Windows 10).