The simplest way in theory anyway would be to network the two PC's. I say in theory because networking can be a pain to set up if the PC's have different operating systems. Microsoft finally made networking easy with Windows 7 but should you want to network an XP PC with Windows 7 can it be a nightmare, I eventually gave up on that one,it was cheaper and better for my sanity and hair to upgrade the better halfs PC to Windows 7.
What is Amazon Go and will it come to the UK? The store without checkouts or queues