What script handles the pop ups?

I have a problem with a pop up and no matter what I can't find the script that has the code. I tried with the developer Toolkit and modules/pages/popupimage, etc and yet I don't seem to find, the script that controls pop ups.

To what pop-ups are you referring to?

taking a shoot in the dark...

any page that makes use of the popup system, which are the
includes/templates/YOUR_TEMPLATE/popup_NAME
includes/modules/pages/popup_NAME
and any language files needed
has to have a script call to the popup which resides in the page folder as in
includes/modules/pages/product_info/jascript_main.php

called within a link as:

<a href="javascript:popupWindow(\\\'' . zen_href_link(FILENAME_POPUP_IMAGE, 'pID=' . $_GET['products_id']) . '\\\')">

the script:

function popupWindow(url) { 
  window.open(url,'popupWindow','toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=no,resizable=yes,copyhistory=no,width=100,height=100,screenX=150,screenY=150,top=150,left=150') 
} 

And that's just a simple popup! if you want to get more advanced, use something like Colorbox..