remove customer and reset id in magento

Run the Query in phpmyadmin.
Note: Before use Backup your database:

    TRUNCATE TABLE `customer_address_entity`;
    TRUNCATE TABLE `customer_address_entity_datetime`;
    TRUNCATE TABLE `customer_address_entity_decimal`;
    TRUNCATE TABLE `customer_address_entity_int`;
    TRUNCATE TABLE `customer_address_entity_text`;
    TRUNCATE TABLE `customer_address_entity_varchar`;
    TRUNCATE TABLE `customer_entity`;
    TRUNCATE TABLE `customer_entity_datetime`;
    TRUNCATE TABLE `customer_entity_decimal`;
    TRUNCATE TABLE `customer_entity_int`;
    TRUNCATE TABLE `customer_entity_text`;
    TRUNCATE TABLE `customer_entity_varchar`;