Hi Vaibahav5555,
Welcome to Microsoft Answers.
We would like to get a better understanding of this issue so we can better assist not
only you but other users with similar problems as well.
Uninstall realtek manager and check if the problem is resolved.
Check for any other software that is running and set to 'mute'. The slider only displays
the status of the volume mixer device, and the device itself is shared between all the programs - if any of them changes the volume, others should move their sliders accordingly. If one program keeps muting the volume, setting it in another won't help.
Also check whether (if you have a laptop or a multimedia keyboard) the 'volume down' key is stuck.
Hope this information is helpful.
Thank you and Regards.
Thahaseena M
Microsoft Answers Support Engineer.
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