Powerpoint Show won't open on web page

[SS]

Using Powerpoint 2007, save the file as a Powerpoint show - the file
extension is .ppsx. When I post this to my webpage (using FrontPage), the
file will not open. However, when I save the file as a Powerpoint 97-2003
Show - file extension .pps, and post it to the website in the exact same
manner, the show opens when you click on the hyperlink. Why won't it open
when I save it with the .ppsx format?

 

[SS]

It won't open on my work computer, and then tried it from home and it won't
open there either. When I save it as an older version (.pps), when I click
on the hyperlink, the show immediately begins. When I save it in the 2007
version (.ppsx), when I click on the hyperlink, I get the "choose Run, Save
or Cancel" box, and if I choose Run (which is what I want the users to be
able to do), I can an error message that it can't open the file.