[b]No you can't convert or upgrade it.[/b] You need to purchase an English version of Vista DVD. Make a [b]clean install[/b] and that's it. Meaning you've got to fully format it as well before installation. Below are links on how to make a clean install of Vista. [b]Make a Clean Install of Vista:[/b] http://www.vistax64.com/tutorials/68767-clean-install.html [b]Useful References:[/b] http://www.timog.com/forum/archive/index.php/t-12257.html http://answers.yahoo.com/question/index?qid=20071004180816AA39e39 http://www.vistaheads.com/forums/microsoft-public-windows-vista-installation-setup/27809-upgrade-japanese-vista-business-us-ultimate.html