Verify SN for Download

I currently have a web site that allows a user to register for a serial number and to download an application. Once they are finished with the on line form, they get an email containing the serial number. In the same email, they are asked to go back to the web site and provide the serial number in order to start the downloading process. Your task will be to create PHP pages to verify the serial number is in the database/table and if the serial number is there [valid], check to see if the user already downloaded the file [application]. If they have [already downloaded], redirect the user to a [login to view URL] page. If not, allow the download to happen and update a different table indicating the user has downloaded the application. Also, the hired coder needs to check the method to which I have placed the "[login to view URL]" file in the table to be sure its correct and can be downloaded by the user. You'll do this by reviewing screen captures I've provided in this projects zip file.