Noob Query: Dynamic URL / View Once URL

Hi All,
Sorry if this is a dumb question but I’ve been searching around and can’t find a way to protect my clients video content.

Can anyone point me in the right direction to find out how to display a page (url) that is unique and destroy that url once it’s navigated away from?

My Situation is:
Site developed that allows people to buy video e-cards.
Full version of the video is shown on preview page so it’s easy to copy the url and send to friends etc.

All that equals a loss of revenue for my client.

Any help appreciated.

Thanks
Steve

have these particular urls make use of a particular directory, e.g.

www.mysite.com/selfdestruct/

use mod_rewrite (assuming apache server) to catch all www.mysite.com/selfdestruct/… type requests and funnel those requests into a single php file in which you get the requested … part and apply the logic you want by either including the requested file or not and update the record of what’s been accessed and what hasn’t.