>I also seem to recall that some VFP upgrades could (or would) look for original installation media, such as a CD. If that's so then you wouldn't have to install VFP6, you would just have to point the VFP9 upgrade installer to the correct drive, it would verify you have the older version, then proceed.

Another similar behavior, probably coming from two dev teams never meeting each other, let alone ever talking, is that if the installation was downloaded, it would be a self extracting zip, which would extract the whole contents into a temp folder, and run the setup from there, and then erase all of it when done.

The trouble arose when you wanted to uninstall or re-run the installation or add an option - it would seem that it never knew that it came from a self-extractor, and that the setup wrote the location of the temp folder as "the medium" (see tagline). Now since the temp folder name was quite intuitive in highland gibberish, you only have to remember the exact spelling, create the directory with that name, run the self extractor again, find where it put the files this time (should be at roughly the same location, these don't change every year), copy all of it to this directory and voila, the system would now find it...

Unless a couple of muscled guys in white smock get you into a retrograde enclosure shirt before you finish this, there should be no problem to complete the operation.