Kingdoms Install/Uninstall Error

[cowsaresomething]

I recently attempted to install M2TW and Kingdoms from CD (not the Gold Edition. Separate CD sets for each.). M2TW installed normally, but the installer said that Kingdoms was already installed (it wasn't). So, I fully uninstalled M2TW (used Windows uninstaller, deleted the SEGA folders, cleared registry entries, deleted the InstallShield Installation Information folder) and tried to reinstall.

The same problem occurred: The Kingdoms installer says that all Kingdoms products are already installed. The M2TW Launcher lists the Kingdoms campaigns but selecting them does nothing (there is no kingdoms.exe to run anyways).

Any ideas what's going on and how to fix it?

[Vifarc]

Same. It says too that the game is already full patched.
There should be an hidden registery key somewhere to be erazed, even after official uninstall and a CCleaner launch.