Huh? As far as I know, PowerPoint is a special software program. Unless it's pre-loaded (as part of MicroSoft Office), or you've loaded it yourself, you probably don't have it. If it is pre-loaded, you should have a desktop icon or an entry in your Start/Programs listing.
Powerpoint has the ability to save a file in such a way that it can be presented for playback on a computer that does not have PP installed, but you need to buy Powerpoint as its own entity, or bundled in a version of Office 97, 2000, XP or whatever if you wish to create your own presentation file.