My check box always submits "Yes"?

I have a checkbox that I have setup to send in a Yes or No value. It was working a while back but for some reason it's only submitting Yes now. 

<asp:CheckBox ID="cbAdminUser" runat="server" />

Dim strAdminUser As String = ""

        If cbAdminUser.Checked = False Then
            strAdminUser = "No"
        ElseIf cbAdminUser.Checked = True Then
            strAdminUser = "Yes"
        End If

		Dim strConnString As String = ConfigurationManager.ConnectionStrings("snfTimeSystemConnectionString").ConnectionString
            Dim con As New SqlConnection(strConnString)
            Dim cmd As New SqlCommand()
            cmd.CommandType = CommandType.StoredProcedure
            cmd.CommandText = "AddPrac"
			cmd.Parameters.Add("@AdminUser", SqlDbType.VarChar).Value = strAdminUser

            cmd.Connection = con

            con.Open()
            cmd.ExecuteNonQuery()
            lblMessage.Text = "Success!!"

            con.Close()
            con.Dispose()

Thanks in advance!