$filename = dirname(__FILE__).'/oldfilename.exe';
$out_filename = 'newfilename.exe';
if (!file_exists($filename)) {
    echo 'Not Found'.$filename;
    exit;
} else {
    // We'll be outputting a file
    @header('Accept-Ranges: bytes');@header('Accept-Length: '.filesize($filename));
    // It will be called
    @header('Content-Transfer-Encoding: binary');@header('Content-type: application/octet-stream');@header('Content-Disposition: attachment; filename='.$out_filename);@header('Content-Type: application/octet-stream; name='.$out_filename);
    // The source is in filename
    $file = @fopen($filename, "r");
    echo@fread($file, @filesize($filename));@fclose($file);
    exit;
}