Some months before i have written a code using PHP to prevent direct file access but now i have modified the previous script since it has some set backs, Let us take one file named MYFILE.PHP as an example, all you have to do is just add the below code on the top of  all the script.

< ?php
if (!empty($_SERVER&#91;'SCRIPT_FILENAME'&#93;) && 'MYFILE.PHP' == basename($_SERVER&#91;'SCRIPT_FILENAME'&#93;))
die ('Please do not load this page directly. Thanks!');
?>

Always remember to change the file name accordingly.I have given that area in BOLD and CAPS