PowerPoint 2003 still works okay. I can open PPT files from within that program.

If I go to the "File Types" dialog box and choose PPT, it says "Opens with: Microsoft PowerPoint". Changing the associated program there behaves the same as right-clicking and choosing "Opens With" -- it doesn't allow me to change to PowerPoint 2003.

I think this is one of those situations where Microsoft is using some special voodoo. Have you heard of advertised shortcuts? With an advertised shortcut, you don't point to an executable file; instead, you point to a program which defined somehow in the registry. My current problem reminds me of advertised shortcuts, but I'm not expert enough to know more than that or how to deal with it.

-TC