If you mean changing the display language of Windows, well, you have to install the language pack first. Now you can only install language packs if you have Professional or Ultimate. For the other versions, there's still some reduced language packs (called LIPs), that can be downloaded, and have their own installer mechanism.After you've installed a language pack, you can change it from control panel > regional options.You can also change locale (that is mainly date, time formats and stuff like that, actually from the same place).?I hope this is what you needed.
