That's weird.
If your Koikatu.exe and InitSetting.exe doesn't have an icon and its just blank then its not installed correctly. If the game starts but nothing shows up then you have to open InitSetting.exe and start the game from there at least once.
That's all I know, sorry. =\
Don't install using the setup.exe or startup.exe. Make sure that you mount both disks first using DAEMON and then start the installation using ILLUSION .msi
That's how I got it to work. Hope that helps.
If you are going to reinstall the game just follow the instructions from foxxyswords, link here. Make sure you install the latest version available.
However, Installing plugins fixed it for me. I just had to install UITranslation.v0.16.0-HoneySelect and everything was back to English for me...