Answer:

Step 1: Download the Foxhound Installshield setup file from the Foxhound home page.

Step 2: Run Installshield setup file; it should display this dialog box when it starts up:

If you see either of these dialog boxes instead, it means you already have a copy of Foxhound 3 installed: In the first case, you can run the Foxhound "unsetup" process before doing Step 2 again (run the Installshield setup file). In the second case, neither Modify nor Repair will work (they won't hurt, but they won't help either)... however, you can use Remove and then do Step 2 again (run the Installshield setup file). The unsetup and Remove processes will not delete your existing Foxhound database. For more information see: Another version of this product is already installed. Why is it called "unsetup" instead of "uninstall"?

Step 3: When the Installshield setup portion of the Foxhound installation is complete, this dialog box will appear; click on the Post-Setup button to continue the installation.

This part is critical; if you don't let the post-setup process run, Foxhound won't be fully installed:

Step 4: When the post-setup process finishes, press Enter to start the Foxhound engine:

At this point, the Foxhound Activation page should appear:

See also...
How do I get a copy of Foxhound?
What are the Foxhound system requirements?
How do I install a new version of Foxhound?
How do I reinstall Foxhound?
Another version of this product is already installed.
Why is it called "unsetup" instead of "uninstall"?
How do I remove Foxhound from my system?