How To Get Row Numbers From SQL Express 2005 Query?

 Hi,
 I'm using SQL Express 2005 and VIsual Studio 2005, and this sounds like it should be easy. I'm trying to return the row numbers of my queries, but if I use the Row_Number() command I get the following error:
 
"The OVER SQL construct or statement is not supported."
 
So, is Row_Number() not supported in SQL Express 2005? If not, how can I return row numbers with my queries? Or, more specifically, how can I return a limited result set from a query (i.e. Return only row number 10-20)?
 
My current command is as follows:
 
 SELECT (SELECT Row_Number() OVER (ORDER BY UserName) As RowNumber), *
FROM Users
ORDER BY UserName 
 
Thanks for any advice you can offer!