HI Faheen,
The best option is restore the old OS via the safe mode Press F8 at the boot and try to go into recovery option as per this article - https://support.microsoft.com/en-us/windows/go-back-to-windows-8-1-40e2d7dc-f640-b0e5-56e1-b41a27e28533
Hope this helps.
JS
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