also just to optimize the php code you have, I would switch to a switch statement instead of going through a ton of if statements.

Also, the code you entered didn't parse correctly, did it? I...

try adding readfile at the end
.....
header('Content-Disposition: attachment; filename="'.$name.'.'.$ext.'"');
readfile($file);
?>

Oops, the
$grade = 5;
is supposed to
$grade = $grade + 5;

It looks like you're calculating them to have full credit if they haven't taken the exam, if that's the case...
if ($_POST['Quiz1'] >= 0 && $_POST['Quiz1'] <= 100)
$grade = $grade +...

Something simple and straightfowrd...

$grade = 0;
if ($_POST['QUIZ1'] >= 0 && $_POST['QUIZ1'] <= 100)
$grade = $grade + $_POST['QUIZ1'] * 0.05;
if ($_POST['Mid-Term'] >= 0 &&...

yes I think that PHP does support some ftp functions (i have no idea how to use those) so that you could log into another off site server and access these files, although this would probably be too...

the other thing you could do with the private section is restrict downloads. Suppose you only want to let your members download certain videos from your website (or any other content) then you can...