Registration Form on Landing Page that Registers User and Downloads Software

I am looking for some help from the amazing WordPress gurus on the forum. I want to implement a registration form on one of my pages that allows the user to register as a user, and once they click the register button, it also downloads the software. The site I want it on is http://www.blindbidpro.com/purchase-now/. If the dual functionality is not possible, is there a way to add a registration form to a page? I have looked for plugins with no luck. Thanks in advance!