REG. XQuery

Hai ,
    
     I am in need to work with xquery in my Asp.Net Application. As described i have added the namespace  

 using Microsoft.Xml.XQuery  

in my application. But when i try to use the methods of xquery it is not instantiating .

I have been thru search for many days .
What should i do to work xquery methods..


Regards,
M.Vanitha.