Query posts by views on category page

Don’t nullify the main query, this breaks stuff. Also, avoid using the $wp_query global as a custom variable. This breaks the main query and causes issues. You can also try adding 'suppress_filters' => true, to your arguments to suppress any custom filters if you are using any custom filters.

Also, don’t use TEMPLATEPATH, it is due to be depreciated according to a recent track ticket. Use get_template_part() instead

Try the following

<?php // The Query
    global $wp_query;

    $term = $wp_query->queried_object;

    $args=array(
        'meta_key' => 'views',
        'orderby' => 'meta_value_num',
        'order' => 'DESC',
        'posts_per_page' => 5,
        'post_type' => 'post',
        'suppress_filters' => true,
        'tax_query' => array(
                array(
                    'taxonomy'  => $term->taxonomy,
                    'field'     => 'slug',
                    'terms'     => $term->slug,
                    )
                )
        );

    $new_query = new WP_Query($args);

    while ($new_query->have_posts()) : $new_query->the_post(); ?>

    <?php get_template_part( category-slider ); ?>

<?php
    endwhile;
    wp_reset_postdata(); ?> 

Apart from this, everything should work, except if you are using query_posts somewhere on the page which will break everything