do not use non-genuine operating system. could harm your pc as they often come riddled with malware.
for a key, you need to buy one from micosoft or a reseller... or use a free linux os. you could choose from various distros to fit your preference.
what you're asking for is piracy and tomshardware does not support piracy. read the forum rules please.http://www.tomshardware.com/forum/277636-28-read-first