i want to add administrator and user right programatically

i create a login page manaully not with the login tollbox control. and also create a registration page.
i distingusih user by user type.
i want that when i login, it check wheather the user type is admin, employee or support team.
if it is admin then it shows the all pages.
if it is employee it hides some hyperlink.
please help me how i set the following condition.
please i shall be very thankful and appreciate if the reply is with some code example.
following are the login.aspx :

<div id="logininfo">
<asp:Label ID="Label1" runat="server" CssClass="as" Text="Login Name:"></asp:Label>
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox><br />
<asp:Label ID="Label2" runat="server" CssClass="as" Text="Password:"></asp:Label>
<asp:TextBox ID="TextBox2" runat="server" TextMode="Password"></asp:TextBox><br />
<asp:Button style=" mar ...