Vista - Japanese Games

First of all, I'm sorry if this is in the wrong thread. If necessary, please move it.

I am running Windows Vista Home basic 32bit SP1 on a Dell Inspirion 1525 laptop. My original version was in English, however I have recently used an unofficial program to change to the Japanese MUI.

The reason I did this was all to play a game that is in Japanese. The only instructions I got to install the game was for XP (go to regional settings, check off the asian language radial and so on) however Vista does not have the same ability. Instead I tried change keyboard (add additional languages) and put Japanese in there. I still got nonsensical symbols and ?????????? when trying to install - and play - the game.

So instead I tried changing my entire system to Japanese. That still left me with the nonsensical symbols like
ƒăƒīş
and ??????

The game is two disks, and everything else seems towork including graphics, audio and some Japanese (i.e. main menu). I even tried downloading different Japanese fonts, including Truetype and Opentype and still to no avail.

Why can I not get the installation and game text to work?