Start with this edit in red
Code:
<?php
/**
 * Page Template
 *
 * Loaded automatically by index.php?main_page=product_info.<br />
 * Displays details of a typical product
 *
 * @package templateSystem
 * @copyright Copyright 2003-2006 Zen Cart Development Team
 * @copyright Portions Copyright 2003 osCommerce
 * @license http://www.zen-cart.com/license/2_0.txt GNU Public License V2.0
 * @version $Id: tpl_product_info_display.php 3435 2006-04-14 03:42:46Z ajeh $
 */
 //require(DIR_WS_MODULES . '/debug_blocks/product_info_prices.php');
?>

<div class="centerColumn" id="productGeneral">
  <!--bof Form start-->
  <?php echo zen_draw_form('cart_quantity', zen_href_link(zen_get_info_page($_GET['products_id']), zen_get_all_get_params(array('action')) . 'action=add_product'), 'post', 'enctype="multipart/form-data"') . "\n"; ?>
  <!--eof Form start-->
  <?php if ($messageStack->size('product_info') > 0) echo $messageStack->output('product_info'); ?>
  <!--bof Category Icon -->
  <?php if ($module_show_categories != 0) {?>
  <?php
/**
 * display the category icons
 */
require($template->get_template_dir('/tpl_modules_category_icon_display.php',DIR_WS_TEMPLATE, $current_page_base,'templates'). '/tpl_modules_category_icon_display.php'); ?>
  <?php } ?>
  <!--eof Category Icon -->
  <!--eof Prev/Next top position -->
  <?php if (PRODUCT_INFO_PREVIOUS_NEXT == 1 or PRODUCT_INFO_PREVIOUS_NEXT == 3) { ?>
  <?php
/**
 * display the product previous/next helper
 */
require($template->get_template_dir('/tpl_products_next_previous.php',DIR_WS_TEMPLATE, $current_page_base,'templates'). '/tpl_products_next_previous.php'); ?>
  <?php } ?>
  <!--eof Prev/Next top position-->
  <?php echo '<div id="leftFloat"' . ' style="width:' . (MEDIUM_IMAGE_WIDTH + 40) . 'px">'; ?>
<!--bof Main Product Image -->
  <?php
  if (zen_not_null($products_image)) {
  ?>
  <?php
/**
 * display the main product image
 */
   require($template->get_template_dir('/tpl_modules_main_product_image.php',DIR_WS_TEMPLATE, $current_page_base,'templates'). '/tpl_modules_main_product_image.php'); ?>
  <?php
  }
?>
  <!--eof Main Product Image-->
   <br class="clearBoth" />