use the following for you sql:
SELECT ps3_categories.CategoryName, ps3_categories.CategoryID, ps3_products.ProductName, ps3_productcategories.ProductID
FROM
ps3_categories
INNER JOIN ps3_productcategories ON ps3_categories.CategoryID = ps3_productcategories.CategoryID
INNER JOIN ps3_products ON ps3_productcategories.ProductID = ps3_products.ProductID
WHERE ps3_products.ProductID = paramProdID
ORDER BY
ps3_products.ProductID ASC,
ps3_categories.CategoryName DESC
Then Create a new parameter in the recordset window:
Name: paramProdID
Type: Number
default Value: -1
Run Time Value: $_GET['ProductID']