Searching files in a directory using vs2008

i want to create a method to search .txt files in a directory ex (c:\files) the directory will mostly be empty and .txt files will be put in this dir.
i want the progrm to keep searching for files like every 20 seconds in the "c:\files" dir and if any .txt files exists then copy it to different dir ex(n:\copyfile) and delete the one in c:\files.