Simplest Way To Connect To Mssql Db

I'm an absolute beginner in asp/asp.net. You have been warned.

I managed to run and compile asp.net using win xp home edition, via Visual Web builder 2005 express edition. I managed to use its tools to create a test database and table and put values in it.

Now I wish to connect to this db using my aspx page. While fiddling around I finally able to drag the "table" icon on the database pane into my aspx page and it generate a code snippet below:

    <div>
        <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataSourceID="SqlDataSource1"
            EmptyDataText="There are no data records to display.">
            <Columns>
                <asp:BoundField DataField="US_ID" HeaderText="User id" SortExpression="US_ID" />
                <asp:BoundField DataField="US_NAME" HeaderText="USer Name" SortExpression="US_NAME" />
            </Columns>
        </asp:GridView>
        <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:nepConnectionString1 %>"
            ProviderName="<%$ ConnectionStrings:nepConnectionString1.ProviderName %>" SelectCommand="SELECT [US_ID], [US_NAME] FROM [USER]">
        </asp:SqlDataSource>
    </div>

 When previewed in the browser, it seems to show the content of the db table. 

What I want to know is a sample coding on how to connect to the db the usual way (initialise the connection string, prepare and execute the query, fetch the content of resultset). Based on the code snippets above (it contains the info about the db name, table name and the column name I'm using), can anyone guide me by providing the lines of codes that retrieve the data?

 Basically the first thing I would like to do is fetching the data to be compared with user name and password submission after they click on login, among other basic stuff, which doesn't require bells and whistles like <gridviews> and other contraptions provided.

And another thing, would the connection string or other parameters be any different from my computer if I were to upload my aspx page including the mssql db file into my webhosting to be tested live?

Thanks for anyone out there willing to provide some hand-holding here!