Where would I disable product purchases from all except...
 

Where would I disable product purchases (remove buy now or change to more details and direct to complete display page for each product) from all pages except fully detailed descriptions on each product?

customer/main/products.tpl for single column layouts, customer/main/products_t.tpl for multi-column. Moving to Template Editing.

oh I was thinking it could be disabled from general setting or something? I guess not?

Thanks

Nope, you will need to comment out or remove the buy now button code on the appropriate template. It should be commented out by default.