Parts of NCC have audited parts of Windows. They just weren't allowed to publish the results.
This has definitely significantly improved the security of Windows, though not given users any kind of protection against malfeasance by Microsoft (including in the sense of giving people malware or simply less-secure new versions of stuff through Windows Update).
This has definitely significantly improved the security of Windows, though not given users any kind of protection against malfeasance by Microsoft (including in the sense of giving people malware or simply less-secure new versions of stuff through Windows Update).