Hi Nimesh0205,
Welcome to Sony Community!
We're sad to hear about your issue. Did you follow the steps provided by Microsoft on how to rollback to Windows 8 ? You might want to consider going to Sony's website, http://www.sony-asia.com/support/product/svf1521ksn, and make sure to download all the updates from there especially the audio driver and software.
For further assistance regarding your concern, please contact the Sony offices/Sony representative offices nearest to your place of residence in Asia Pacific region http://www.sony-asia.com/countryselector.html?hpid=countryselector:AsiaPacific. Due to proximity, they are in a better position to respond to your questions or concerns.
Regards,
Jen
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