apostrophe fread problem! HELP!

[champoi]

my program opens a text file that was stored earlier, but the problem is that when i echo it, the apostrophe that was stored in the text file, when echoed, is replaced by a question mark in the page displayed, help! these are my codes:

 

<?php
  $f1 = fopen($directory."/geninfo.txt","r");
  echo "<p>".nl2br(fread($f1,"23554432"))."</p>";
  fclose($f1);
?>