Display Balloon if Value from WebClient is met
===

I am a total C# Novice and have recently successfully programmed a Live Chat application in PHP, AJAX, JQuery however i now need to create a very small windows app, I literally just want an icon on my System Tray that polls a specified URL that returns "1" or "0"

1 = Pending Chats
0 = No Chats

I've followed loads of tutorials and have come up with the code below.

My intention was to comment out "number = number + 1;" to cause the loop to run endlessly.
This code looks to me like it should work, However when i run the code it just flashes the balloon up 25 times (every cycle of the loop).

Now, I don't want it to prompt me every millisecond when the loop is ran, i want it to prompt then sleep for 15 Seconds, then prompt again until the chats are gone.

Anyway, the balloon is showing up, however when there is 0 chats and the url displays "0" it doesnt work. i also tried doing it leaving the URL Blank if there are no chats.

any help would be massively appreciated, I did a lot of searching and couldnt find anything specific to this type of if/else.

    using System;
    using System.Net;
    using System.Windows.Forms;
    using System.Threading;
    using System.Drawing;

    namespace WindowsApplication9
    {
    static class Program
    {
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            NotifyIcon notifyIcon1 = new NotifyIcon();
            ContextMenu contextMenu1 = new ContextMenu();
            MenuItem menuItem1 = new MenuItem();
            contextMenu1.MenuItems.AddRange(new MenuItem[] { menuItem1 });
            menuItem1.Index = 0;
            menuItem1.Text = "E&xit";
            menuItem1.Click += new EventHandler(menuItem1_Click);
            notifyIcon1.Icon = new Icon("C:/Users/Gavs/Downloads/favicon.ico");
            notifyIcon1.Text = "GigaChat TaskBar V1";
            notifyIcon1.ContextMenu = contextMenu1;
            notifyIcon1.Visible = true;
            notifyIcon1.BalloonTipIcon = ToolTipIcon.Info;
            notifyIcon1.BalloonTipTitle = "New Chat Request";
            notifyIcon1.BalloonTipText = "You Have Peding Chats.";

            int number = 0;
                while (number < 25)
                {
                    WebClient wc = new WebClient();
                    string pendingChats = wc.DownloadString("http://dev.gigavm.com/live/ext/logistics.php?status=Pending");

                    if (!String.IsNullOrEmpty(pendingChats))
                    {
                        int chats = 1;
                        notifyIcon1.ShowBalloonTip(5000); 
                    }
                    else
                    {
                        int chats = 0;
                    }
                    number = number + 1;
                }

            Application.Run();
            notifyIcon1.Visible = false;
        }

        private static void menuItem1_Click(object Sender, EventArgs e)
        {
            Application.Exit();
        }
    }
}