Free Shipping Options freeoptions will run with ALL of the other shipping modules based on its configuration ...

Free Shipping freeshipper will ONLY run when there is $0.00 shipping cost based on:

1 Product is marked Always Free Shipping

2 Product is marked 0 weight and 0 weight is set to mean Free Shipping and only 0 weight products are in the cart

Shipping Modules are Installed/Removed in the Modules ... Shipping ... of your Zen Cart Admin ...

Click on the Module you want removed and click on REMOVE ...