Different ways to remove wp dashboard widgets. I think disable_dash.php is considered the best method.

disable_dash.php

//* REMOVE DASHBOARD WELCOME
remove_action('welcome_panel', 'wp_welcome_panel');
// */


//* REMOVE ADMIN DASHBOARD WIDGETS

// Create the function to use in the action hook
function remove_default_dashboard_widgets() {
	
    // Main column:
    remove_meta_box( 'dashboard_browser_nag', 'dashboard', 'normal' );
    remove_meta_box( 'dashboard_right_now', 'dashboard', 'normal' );
    remove_meta_box( 'dashboard_recent_comments', 'dashboard', 'normal' );
    remove_meta_box( 'dashboard_incoming_links', 'dashboard', 'normal' );
    remove_meta_box( 'dashboard_plugins', 'dashboard', 'normal' );
	
	
  	// Side Column:
  	remove_meta_box( 'dashboard_quick_press', 'dashboard', 'side' );
    remove_meta_box( 'dashboard_recent_drafts', 'dashboard', 'side' );
    remove_meta_box( 'dashboard_primary', 'dashboard', 'side' );
    remove_meta_box( 'dashboard_secondary', 'dashboard', 'side' );
	
} 

// Hook into the 'wp_dashboard_setup' action to register our function
add_action('wp_dashboard_setup', 'remove_default_dashboard_widgets' );

// */

disable_dash_core.php

	/* Disable WordPress dashboard widgets

function remove_default_dashboard_widgets() {  
  
    remove_meta_box('dashboard_right_now', 'dashboard', 'core');  
    remove_meta_box('dashboard_recent_comments', 'dashboard', 'core');  
    remove_meta_box('dashboard_incoming_links', 'dashboard', 'core');  
    remove_meta_box('dashboard_plugins', 'dashboard', 'core');  
    remove_meta_box('dashboard_quick_press', 'dashboard', 'core');  
    remove_meta_box('dashboard_recent_drafts', 'dashboard', 'core');  
}  

// USES ADMIN MENU --- NOT SURE WHY MAYBE OLD?
add_action('admin_menu', 'disable_default_dashboard_widgets');


// */

unset_dash.php

/* UNSET WordPress dashboard widgets
	
function remove_dashboard_widgets(){
  global$wp_meta_boxes;
  unset($wp_meta_boxes['dashboard']['normal']['core']['dashboard_plugins']);
  unset($wp_meta_boxes['dashboard']['normal']['core']['dashboard_recent_comments']);
  unset($wp_meta_boxes['dashboard']['side']['core']['dashboard_primary']);
  unset($wp_meta_boxes['dashboard']['normal']['core']['dashboard_incoming_links']);
  unset($wp_meta_boxes['dashboard']['normal']['core']['dashboard_right_now']);
  unset($wp_meta_boxes['dashboard']['side']['core']['dashboard_secondary']); 
}
 
add_action('wp_dashboard_setup', 'remove_dashboard_widgets');
	
// */