I have nothing against you srsly...
but as i remember thats windows 7...8...etc if free to download from google isnt ?
yes yes thats right there's key u should have it.You can download the OS but this is the key to authenticate it.
From Microsoft:
- If you will be installing the operating system for the first time, you will need your Windows product key (xxxxx-xxxxx-xxxxx-xxxxx-xxxxx). For more information about product keys and when they are required, visit the FAQ page.

