try
                {
                    String fileToUpload = "C:\test.txt";
                    String sharePointSite = "http://localhost:80/";
                    String documentLibraryName = "test";
                    SPSecurity.RunWithElevatedPrivileges(delegate()
                    {
                    using (SPSite oSite = new SPSite(sharePointSite))
                    {
                        using (SPWeb oWeb = oSite.RootWeb)
                        {
                            oWeb.AllowUnsafeUpdates = true;
                            if (!System.IO.File.Exists(fileToUpload))
                                throw new Exception("File not found.");

                            SPDocumentLibrary myLibrary = oWeb.Lists[documentLibraryName] as SPDocumentLibrary;

                            // Prepare to upload
                            Boolean replaceExistingFiles = true;
                            String fileName = System.IO.Path.GetFileName(fileToUpload);
                            FileStream fileStream = File.OpenRead(fileToUpload);

                            // Upload document
                            SPFile spfile = myLibrary.RootFolder.Files.Add(oWeb.Url.ToString() + "/" + myLibrary.Title.ToString() + "/" + fileNameWithoutExt + fileExtName, fileStream, replaceExistingFiles);

                            // Commit 
                            spfile.Update();
                            myLibrary.Update();
                            oWeb.Update();
                            oWeb.AllowUnsafeUpdates = false;
                        }
                    }
                    });

                }
                catch (Exception SPError)
                {
                    Response.Write(SPError.Message);
                }