Once you have your genuine , you need to install it. Here is the standard process for a modern UEFI or Legacy BIOS system.
Once you've downloaded the ISO file, it's essential to verify its integrity to ensure it's not corrupted or tampered with. You can use tools like SHA-1 or MD5 to verify the hash value of the ISO file. windows 7 professional original iso 64 bit
Do not just copy the ISO to a USB drive. Use (free, open-source) or the official Windows USB/DVD Download Tool. Once you have your genuine , you need to install it