I don't have any personal experience with Japanese, and there are few, if any, Japanese members of this forum, I'm afraid.
Trying http://www.google.com/search?hl=en&lr=&q=%22word+2000%22+japanese&btnG=Search however gives some promising hits. The second one tells: " I haven't experienced any problems so far making Japanese documents with Word 2000."
Without having read any of the hits, I suppose you might need a Japanese version of Windows, MS Office or keyboard. I don't think it will work with the out-of-the-box version of an American PC equipped with MS Word. But I assume the Japanese community in the USA is large enough to get personal help, if needed.
Hope this helps.
Does Word 2000 support vertical writing in Japanese?