The Windows 8 Official ISO images hosted on Microsoft’s servers are genuine and official versions, and the downloads from the server are totally free and definitely legal. Yes, there’s a catch: this is a trial version. You can download Windows 8 official ISO but it will work for 90 days, and it’s designed for hardware and software developers to test their products on.
If you’re interested in downloading Windows 7 – Click here.
Anyway, without a genuine and legally purchased product key, you can’t get Windows 8 activated, and as mentioned – Windows 8 will only run as evaluation copy for up to 90 days.