Here is a method to find windows key from your bios bin file.
First open your bios dump file with HxD editor and find this hex string.
Find: 01 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00 1D 00 00 00
In this way you can easily find your windows key from your bios bin file.
Download HxD Hex Editor from below link !