Confirm Presentation was watched

Hi,
I need to figure out how to have a presentation on a website. A user will login, they would need to view the presentation, and then after the presentation is finished they would need to be added to a database or text file, somewhere to log that they have watched the presentation.

Now the only aspect of this that I am stumped on is how would I go about verifying that they watched the entire presentation.

I doubt that this can be done with a powerpoint, I figured the presentation would have to be converted to flash.

Does anyone know of existing software to convert a powerpoint to flash, along with displaying the flv file and then submitting data to a php script or something when it has finished.

Any ideas would be helpful, I can't find anything about this.

Thanks

I don't know how you would do the conversion and stuff...but couldn't you embed a link at the end of the presentation that has a special database stored string in it?