function off_widgets() {
unregister_widget('WP_Widget_Pages'); //Page Widget
unregister_widget('WP_Widget_Calendar'); //Calender Widget
unregister_widget('WP_Widget_Archives'); //Archive Widget
unregister_widget('WP_Widget_Links'); //Links Widget
unregister_widget('WP_Widget_Meta'); //Meta Widget
unregister_widget('WP_Widget_Search'); //Search Widget
unregister_widget('WP_Widget_Text'); //Text Widget
unregister_widget('WP_Widget_Categories'); //Categories Widget
unregister_widget('WP_Widget_Recent_Posts'); //Recent Posts Widget
unregister_widget('WP_Widget_Recent_Comments'); //Recent Comments Widget
unregister_widget('WP_Widget_RSS'); //RSS Widget
unregister_widget('WP_Widget_Tag_Cloud'); //Tag Cloud Widget
unregister_widget('WP_Nav_Menu_Widget'); //Menus Widget
}
add_action('widgets_init', 'off_widgets', 11);