SQL Server :: How To Check If A Record Exists In VWD?

I am very new to this and have watched a lot of the videos. While trying out VWD2010 and SQL2008 Express, I come across many things, I just don't know how to do. Here is the latest:

I have a Table
UserId - Int - AutoIncrement
FirstName - Var(10)
LastName - Var(10)

I also have an ASP web page that allow the user to enter a first name and last name. It also has a button to submit. What I would like to do is have a Select statement check to see if the name already exists, then send a comment back to the user via a label. If it doesn't exist, then I would like to Insert the info and then again inform the user via label.

SelectCommand="SELECT COUNT (UserId) FROM Users WHERE ((FirstName=@FirstName) and (LastName=@LastName))"
InsertCommand="INSERT INTO User(LastName, FirstName) VALUES (@FirstName, @LastName)"
<InsertParameters>
<asp:ControlParameter ControlID="tbFirstName" Name="FirstName"
PropertyName="Text" Type="String" />
<asp:ControlParameter ControlID="tbLastName" Name="LastName"
PropertyName="Text" Type="String" />
</InsertParameters>
<SelectParameters>
<asp:ControlParameter ControlID="tbFirstName" Name="FirstName"
PropertyName="Text" Type="String" />
<asp:ControlParameter ControlID="tbLastName" Name="LastName"
PropertyName="Text" Type="String" />
</SelectParameters>

On the code behind, I get lost. (Obviously this doesn't work, but I don't know how to go about getting a results back. Protected Sub bSubmit_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles bSubmit.Click

SqlDataSource1.Select(DataSourceSelectArguments.Empty)
(get a return)
(check return value, if <>0 then
lblResults.Text = "exists!"
else
SqlDataSource1.Insert()
lblResults.Text="added!"
end if)
End Sub