I used the following code of how to write a text file in .net..but i had an error could not open the path..how can i rectify it

extWriter tsw = new StreamWriter(@" C:\Hello.txt");

//Writing text to the file.
tsw.WriteLine(" Hello");

//Close the file.
tsw.Close();

//Launch the file.
Process.Start(@ "C:\Hello.txt") ;

please help me as soon...