Go4Expert - a file doesn't want to be deleted or overwritted

Hi all,
I've a problem with a file! but i think this is due to a code error i can't see.
My program create a file with some information within. Then I search the information into the file, I fine them, and write them to screen (I use visual studio pro evaluetion ^^) with some textbox.. then I give the possibility to modify or delete the content found, to do this i make a string of all file (i will quote my code!) then i search use the replace string.replace("before";"after");, but this is not the problem. Now I've my string with all file modified, and ready to replace the all the old file! So i decide do rewrite all the file with the new string, but it doesn't change. If i decide to save it to a new file, than it works... but I don't need this!

Code:

/* Already created string named elimina (i'm italian..) with the content i want to delete in the file, and the string fileContent, with all the file content.*/ 

            try

            {

                //Pass the file path and file name to the StreamReader constructor (some comments are of the msdn, not mine :D)

                StreamReader sr = new StreamReader("lista.txt");   // file name is lista.txt into the folder of the executable



                fileContent = sr.ReadToEnd();  // taken all the file

                 

                fileContent = fileContent.Replace(elimina, "");   // deleted from the new string what I don't want anymore



                 

                //close the file

                sr.Close();

                Console.ReadLine();



       

            }

            catch (Exception f)

            {

                Console.WriteLine("Exception: " + f.Message);

            }

            finally

            {

                Console.WriteLine("Executing finally block.");

            }

             



            /* Now I try to overwrite all the file lista.txt with the new string fileContent */



             try

             {

                 //Open the File

                 StreamWriter sc = new StreamWriter("Lista.txt", false);



                 sc.Write(fileContent);





                //close the file

                sc.Close();

            }

            catch (Exception de)

            {

                Console.WriteLine("Exception: " + de.Message);

            }

            finally

            {

                Console.WriteLine("Executing finally block.");

            }

This code give no error, but it doesn't work. If in the second stream of file I choose to write into a file named "what i want.txt" it works perfectly, creating the new file and writing on it the new content i wanted.

Thanks for reading, and sorry for my italian-school english! (No good teacher... XD)