c# RegExp

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.Media;
using System.Runtime.InteropServices;
using System.Text.RegularExpressions;






namespace DME
{
	class Program
	{
    	[DllImport("winmm.dll")]
    	public static extern void PlaySound(string path, int mod, int flg);


    	static void Main(string[] args)
    	{
        	WebClient siteurl = new WebClient();
        	string source = siteurl.DownloadString("http://online-hiorg.square7.de");
        	string oldsource = source;


        	string @scriptdir = System.Threading.Thread.GetDomain().BaseDirectory;
        	Console.WriteLine(@scriptdir);
        	Console.WriteLine(@scriptdir + "alert.wav");


        	while (true)
        	{


            	//Load Source.
            	source = siteurl.DownloadString("http://online-hiorg.square7.de");


            	if (source != oldsource)
            	{
                	Console.WriteLine("Alarm!");


                	PlaySound(@scriptdir + "alert.wav", 0, 0x0000);


                	// Define a regular expression for repeated words.
                	Regex rx = new Regex(@"(?s)<td>.+?</td>.+?<td>(.*?)</td>",
                  	RegexOptions.Compiled | RegexOptions.IgnoreCase);


                	// Define a test string.    	
                	string text = source;


                	// Find matches.
                	MatchCollection matches = rx.Matches(text);


                	// Report the number of matches found.
                	Console.WriteLine("{0} matches found in:\n   {1}",
                                  	matches.Count,
                                  	text);


                	// Report on each match.
                	foreach (Match match in matches)
                	{
                    	GroupCollection groups = match.Groups;
                    	Console.WriteLine("'{0}' repeated at positions {1} and {2}",
                                      	groups["word"].Value,
                                      	groups[0].Index,
                                      	groups[1].Index);






                	}


                	oldsource = source;
            	}
        	}
    	}
	}
}