Generating text file dynamically and display it in new browser window with asp.net and C#

I have created text file and added content to it.After this i want above generated text file should display in web browser and can save file as .txt format. Plz help, i tried max. thanks in advance.

FileStream fs = new FileStream("D:\\overflow.txt", FileMode.OpenOrCreate, FileAccess.Write);
StreamWriter writer = new StreamWriter(fs);
writer.Write("Hello Welcome");
writer.Close();