Well, it depends. The best thing to do is to buy a license key to activate Windows legally and to be certain that your copy is genuine. Check this link for guidance about Windows activation.
However, if you still want to use KMSPico, be very careful where you download it. There are a lot of versions altered with malware on the Web! I recommend you to download it from CCM, as we guarantee that the file is malware-free and secure - here's the download link.