Hi,
If you remove the main product, it removes the options, it's normal because an option is attached to a product, if the product is removed ,so the options too.
To allow, for example, many hard drives your option product can be configured with characteristics, the add to the hdd product the variants 1x500, 2x500, ...
Then in the product page, when you choose hard drive you can select the number wanted.
You can find a demo here, and see how it's configured in the backend:
demo.hikashop.com/index.php?option=com_h...ow&Itemid=91&lang=en