Math,
I think that the easiest way to do this is to add a new top layer to your VI that is two string controls, one for a login and one for a password. If this check passes, then you can either run your original VI as a subVI with the show front panel when called option on (and close if originally closed) or to have all of your original VI hidden and show it when the login passes. Both of these methods will be quick and simple to implement and will allow you to do what you would like through only the LabVIEW Web Server.
Randy Hoskin
Applications Engineer
National Instruments
http://www.ni.com/ask