How to deregister scripts all at once

Its already answered on this link

<?php
//To remove all script from the page
function remove_all_scripts() {
    global $wp_scripts;
    $wp_scripts->queue = array();
}
//  to remove all stylesheet
add_action('wp_print_scripts', 'remove_all_scripts', 100);

function remove_all_styles() {
    global $wp_styles;
    $wp_styles->queue = array();
}
add_action('wp_print_styles', 'remove_all_styles', 100);
?>

It will remove all the scripts enqueued by standard method. Manual script will not be removed.

Hope it will help