I have a Lenovo Z580, which has a pre-installed copy of Windows 8.
I want to install only Ubuntu & Windows 7 on it, so I want to format the whole hard-drive. However, I'd like to retain the product key, so that I can re-install Windows 8 in the future.
Now, how do I obtain the product key? Also, if I want to re-install Windows 8, how do I get a legitimate ISO or CD, without paying any extra money?