query regarding filtering of data in crystal report 9

Question

Hi all,
its me anshul a new member of this group.
I have a problem plz help me.

I want to generate a report by taking parameters from the user. i take the parameter from the user but the report does not prompt for the parameter. i use vb.net as front end and sql server2000 as back end. I am using a new connection (oledb) for generating the report and a command to select the data as
select emp_Id, emp_name from Employee_Master where emp_Id={?emp_Id}

It ask me for enter a value what should i do???