I've never heard of WMI being disabled. It's an integral part of Windows and many important services depend on it, such as the Windows Firewall. While this may be true in some heavily restricted corporate environments, it's almost never true for regular users.

Also it's pretty hard to beat this one-liner that always returns the correct version:

Code:
Debug.Print GetObject("winmgmts:").InstancesOf("Win32_OperatingSystem").ItemIndex(0).Version
Still, "KUSER_SHARED_DATA" wins hands down.