Oh, i haven't looked at language changes in windows, ah here we go... A Few links that may help you:
http://windowshelp.microsoft.com/Win...7512d1033.mspx
That says something about language files and theres a link further down about getting them... i'm sure that may help... I've looked around more and that seems to be how you change the entire interface...
Cheers,
Jamey