How to change system default regional settings in windows XP?

How can I change the system-default regional settings in windows XP for use by services (run by the system user)?

Regional and Language Options in the control panel modify the settings for the logged-in user. However, services don't use the user's settings - they use the system settings. I know that they can be found in the registry here:

HKEY_USERS\.DEFAULT\Control Panel\International

My question is: What mechanism is there for changing the system-language/date/etc from en-us to en-gb?

How do I change my region on Windows XP?

Windows XPClick on “Regional and Language Options”, which will either be its own icon, or behind the category “Date, Time, Language, and Regional Options”. In the “Regional and Language Options” window, ensure that the format is set to “English (United States)”, and click on the “Customize” button as shown below.

This was helpfull for me "Apply regional and language settings to reserved accounts".

In short (Windows 7): Open "Region and Language" dialog, then click the "Administrative" tab, and then click "Copy settings...", select "Welcome screen and system accounts", OK.