Force download

<?php 
    //Set this to the base of where files  
    //can be downloaded from for security measures. 
    $basedir = "D:/wwwroot/"; 
    if(!$_GET['file']) { 
        print "Sorry that file does not exist"; 
        exit; 
        } 
    elseif(!file_exists($basedir.$_GET['file'])) { 
        print "Sorry that file does not exist"; 
        exit; 
        } 
    else { 
        header("Content-Type: octet/stream"); 
        header("Content-Disposition: attachment; filename=\"".$_GET['file']."\""); 
        $fp = fopen($basedir.$_GET['file'], "r"); 
        $data = fread($fp, filesize($basedir.$_GET['file'])); 
        fclose($fp); 
        print $data; 
    } 
?>