EarlyFloyd

Please note I haven't tested this and use at your own RISK... as always TEST first before use on a live site and always BACK UP....

PHP Code:
UPDATE products SET products_status = '1' WHERE master_categories_id = 'x' and manufactures_id = 'y'; 
This should update the product status to active in all the products in the top level category down wards of your top category 'y' with manufacturer 'x'.

(y and x are the id numbers of the category and manufacturer which you can find in your database via phpMyAdmin in the products table)

A very good site for learning SQL for Mysql is tizag you just remove the ' $result = mysql_query(" ' to use pure sql in the Zen Carts SQL Query Executor, always end your SQL with ';'.