Tips for a safe and reliable system

Source

• When downloading a software from the Internet, always check its authenticity by matching its HASH with the one provided by its official editor (e.g. Microsoft).
• Only download updates for Windows through Windows Update or from Microsoft.com. Do not install leaked updates, since there are no HASHES available from Microsoft's website, nor any certitude that these updates will be ever released officially, nor any guarantee that it's not malicious software.
• Do not run .exe files found on P2P networks, forums, blogs, or unknown websites. Always perform a virus check when you don't trust the download source.
• Do not install anything that modify system files, including (but not limited to) Chew-WGA, RemoveWAT from Hazar, Toolkit 1.8 from Orbit30, and other similar tools that imply changing the way the operating system works by disabling or modifying main features (such as activation modules) or crucial characteristics (such as edition integrity) also known as "Frankenbuild monster".