When we click on the following powerpoint file resouce, a blank page will be displayed.
 1. Resource type: ppt (Powerpoint file)
 2. Window: new window

To prevent this blank page, we can modify mod/resource/type/file/resource.class.php as below.

Index: resource.class.php
===================================================================
RCS file: /cvsroot/moodle/moodle/mod/resource/type/file/resource.class.php,v
retrieving revision 1.68
diff -u -r1.68 resource.class.php
--- resource.class.php 19 Jul 2007 05:51:33 -0000 1.68
+++ resource.class.php 19 Jul 2007 22:51:38 -0000
@@ -605,6 +605,9 @@
             echo '</div>';
             echo "<div class=\"popupnotice\">(<a href=\"$fullurl\">$fullurl</a>)</div>";
         }
+ if ($mimetype == "application/vnd.ms-powerpoint") {
+ $fullurl = $fullurl . "?forcedownload=1";
+ }
         redirect($fullurl);
     }