English versions of W2K and XP support the standard Japanese 106 key keyboard layout, which can be selected from Control Panel\Keyboard.

This may entail installing support for Japanese when setting up the OS (I don't recall if it works without, since all my computers have it).

Nonstandard Japanese layouts (some laptops, etc.) require their own drivers.


The main problem will be getting support for this computer's custom hardware, if any: XP drivers obviously exist, and you'll want to preserve access to them from the original Japanese boot drive (or copy it onto another partition), since the installation CD is probably a compressed OS restore disk as opposed to a CD with discrete folders including drivers. Otherwise, a Japanese-reading friend could locate them for you on the NEC website.

Once the drivers are installed, you'll have to find English software that fully takes advantage of the hardware; in my experience country-specific hardware such as TV tuners are a problem.