The 64-bit version of Vista will have PatchGuard technology installed in it which prevents all access to the kernel. (link
) This has gotten Symantec and other folk upset with MS since, in the past, MS has provided means (basically looked the other way) of getting into kernel mode through their hooking APIs. PatchGuard essentially nixes the ability to hook into the kernel, at least for write-access. MS says OneCare will be treated the same as all other 3rd party anti-virus/anti-spyware applications in this regard. It's strange that MS on one hand closes shuts out the AV technology and on the other hand opens embraces it with OneCare.