Sounds like your file associations are broken.
See: http://pptfaq.com/FAQ00355.htm

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Thanks,
Glenna Shaw
Microsoft PowerPoint MVP Team
http://www.pptmagic.com
> When I try to open Powerpoint or open a PPT document, the Windows Installer
> box opens telling me to insert MSXP Professional Frontpage disk.
>
> I am not able to access Powerpoint.
>
> I'd appreciate any suggestions.
This kind of thing sometimes happens when you have mixmatched MSI
(installer) files from different versions of Office -- or a version of
Office and then a different version of a product like FrontPage or OneNote,
etc. And it seems that, even if you fix it, it will sometimes happen again
after installing a service pack. I think. I could be dreaming on that last
one. ;-)
Anyway, if you put in the FrontPage install disk and let it do its thing,
does that resolve the problem?

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> When I try to open Powerpoint or open a PPT document, the Windows
> Installer
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>
> I'd appreciate any suggestions.