If you need to reset a database to empty (no products but keeping the configuration settings), then take the following and paste it into a PHPMyAdmin sql window and you should be good to go.
Code:
DELETE FROM `address_book`;
DELETE FROM `banners`;
DELETE FROM `banners_history`;
DELETE FROM `categories`;
DELETE FROM `categories_description`;
DELETE FROM `counter`;
DELETE FROM `customers`;
DELETE FROM `customers_basket`;
DELETE FROM `customers_info`;
DELETE FROM `manufacturers`;
DELETE FROM `manufacturers_info`;
DELETE FROM `orders`;
DELETE FROM `orders_products`;
DELETE FROM `orders_status_history`;
DELETE FROM `orders_total`;
DELETE FROM `products`;
DELETE FROM `products_attributes`;
DELETE FROM `products_attributes_download`;
DELETE FROM `products_description`;
DELETE FROM `products_notifications`;
DELETE FROM `products_options`;
DELETE FROM `products_options_values`;
DELETE FROM `products_options_values_to_products_options`;
DELETE FROM `products_to_categories`;
DELETE FROM `reviews`;
DELETE FROM `reviews_description`;
DELETE FROM `sessions`;
DELETE FROM `specials`;
DELETE FROM `whos_online`;
ALTER TABLE banners AUTO_INCREMENT = 1;
ALTER TABLE banners_history AUTO_INCREMENT = 1;
ALTER TABLE categories AUTO_INCREMENT = 1;
ALTER TABLE customers AUTO_INCREMENT = 1;
ALTER TABLE customers_basket AUTO_INCREMENT = 1;
ALTER TABLE customers_basket_attributes AUTO_INCREMENT = 1;
ALTER TABLE manufacturers AUTO_INCREMENT = 1;
ALTER TABLE manufacturers_info AUTO_INCREMENT = 1;
ALTER TABLE orders AUTO_INCREMENT = 1;
ALTER TABLE orders_products AUTO_INCREMENT = 1;
ALTER TABLE orders_status_history AUTO_INCREMENT = 1;
ALTER TABLE orders_total AUTO_INCREMENT = 1;
ALTER TABLE products AUTO_INCREMENT = 1;
ALTER TABLE products_attributes AUTO_INCREMENT = 1;
ALTER TABLE products_description AUTO_INCREMENT = 1;
ALTER TABLE products_options_values_to_products_options AUTO_INCREMENT = 1;
ALTER TABLE reviews AUTO_INCREMENT = 1;
ALTER TABLE specials AUTO_INCREMENT = 1;
DELETE FROM `orders`;
DELETE FROM `orders_products`;
DELETE FROM `orders_status_history`;
DELETE FROM `orders_total`;
ALTER TABLE orders AUTO_INCREMENT = 1;
ALTER TABLE orders_products AUTO_INCREMENT = 1;
ALTER TABLE orders_status_history AUTO_INCREMENT = 1;
ALTER TABLE orders_total AUTO_INCREMENT = 1;
