There is a large battle forming over what Windows Vista should, or should not, have in it. Security Center is the Windows component that monitors the overall security health of the system. PatchGuard, a feature unique to the 64-bit edition of the operating system, is a unique component called Patch Guard. If Microsoft keeps to its plan of restricting access to the kernel, it could lead to greater security, reliability, and consistency in the offering. The question is whether any third party should be allowed unfettered authority to alter the kernel.”]
Source: https://www.darkreading.com/analytics/deconstructing-vista