keyboard issue...

I installed Windows 7 32 bit after wiping my wife's Japanese Dell laptop which had XP home verision on it. I had a big problem that turned out to have a simple solution. I had the number lock on so the keyboard was typing numbers where there should have been letters. Anyways. In order to overcome that obstacle I mistakenly reinstalled Win 7 2x and the last time was with English as the default language and English keyboard. Now my wife, who is Japanese, would like her keyboard to be on a Japanese layout but I cannot seem to get it right by adding the Japanese keyboard through the control panel and setting that to the default keyboard. Even deleted the English keyboard and the problem persists. Any ideas? Do I have to reinstall Windows again with Japanese as the default language and keyboard? Thanks.
-Sam