hi,
Well no idea why it happens ... what I mean is that you out in English by default and allows you to choose the language in Spanish, thus no need to install the Spanish language and I is installed.
Go to Control Panel> Clock, Language, and Region.
By clicking on Language.
You appear several languages, the default is the first, so you have to put the first in Spanish, you choose and you raise (up).
After you click on "options" of the Spanish language, inside is an option that is "Convert this language in the primary" or similar, use it, is that I have only one language and I can not see exactly.
You will be asked to restart the computer or the session, do it and it should be worth.
So when you feel completely out new accounts in Spanish, you should make this final step:
Go to Control Panel> Clock, Language, and Region.
Click on region.
Go to "Administrative" tab.
Click "Copy Settings ...".
You should leave everything in Spanish, if so:
Activates the "logon screen and system accounts" box.
Activate the "New User Account" box.
Accept and restart the computer.
regards