Installing/Uninstalling Valkyria games

So I wanted to reinstall a Valkyria game I had installed before, and the installer detects it as installed. So I can't install it. Nor can I uninstall it because there are no game files (I typically manually delete stuff cuz who wastes time using an uninstaller).

I scoured the registry files and deleted every instance I could find of the game, but no luck. I can't just unpack the disc because the game files are in a .dat file that there is no universal unpacker (as far as I know) for.

Anyone got an idea? Can I hex the installer in some way to make it work?

Unfortunately I still have issues with this... Anyone got any ideas now?

EDIT: NEVERMIND.

I wasted so much time scouring the registry (cause you know, you usually have install data THERE) while the whole time in the documents folder was a VALKYRIA folder with the installation data in it. Holy shit.

Hope this helps someone else at least.