Hi @erasmusf
When you register your games with Origin, the game codes are automatically associated with your account and you have access to your games at any time. To find the product code and the download button, simply log into your Origin account and go to "My games". There, look for the NFS HP cover (If it's not visible, make sure to toggle "Show all games")
Once you have located the game you want to download again, mouse over the cover and click on the grey "i" icon.
If you haven't registered the game in Origin you will need to contact a Game advisor with the original proof of purchase so they can assist (more info here).
Finally, when you buy a second hand game or a new game that is incomplete, simply take it back to your retailer for an exchange.
Hope that helps.
