I'm having a problem with my pdf file download link on my download page. When I set my link for them to get their product, I want the window to close so that they can't go back and bookmark the page to do whatever they want with it. Anyone know how to make it automatically close after they've clicked the link? Or is there another way to do this, so that they can't get back to the same download page after they're done saving the ebook? I hope this makes sense, it's so hard to explain. Any answers would be appreciated.

The only way that you can stop them reloading the page is if you have some server side processing to check if they are allowed access. For example if you set up an entry in a database when they pay for access and have the download link delete that entry to indicate that they have already downloaded.