If you mean from your question you are looking to programmatically shut down Windows from within LabVIEW, it is possible to do this using functions found in the LabVIEW Windows API Function Utilities - see following link:
http://zone.ni.com/devzone/explprog.nsf/6c163603265406328625682a006ed37d/ebf11dd1f0feaef3862566790072a983?OpenDocument
Jeremy
There is a VI inside this library that will allow you to shutdown the operating system