ScubeduFan--From the link that war1 provided in the first response post.
"The Internet Explorer 7 MUI is a set of language-specific resource files that may be added to the English version of Windows with the OS MUI pack and Internet Explorer 7 installed. "
"The OS MUI language pack for the desired MUI language must be installed."
If that means what it says, you need a Windows MUI to be installed.
The OS MUI's are available only under a very expensive multiuser license.
What is a Windows MUI?
"Multilingual User Interface Pack is a set of language specific resource files that can be added to the English version of Windows Professional. When installed on the English version of Windows, MUI allows the user interface language of the operating system to be changed according to the preferences of individual users to one of the 33 supported languages. This allows large corporations to roll out the same worldwide image with a single install job."
I do not think you can change the Windows/IE buttons/icons for free if you use a Windows OS before Vista. You will have to buy a version of Windows in Spanish. (I assume you will not want to pay for the OS MUI.)
There does seem to be the possibility of getting some help for the high end versions for Vista
http://www.mydigitallife.info/2007/11/21/windows-vista-mui-language-packs-for-x86-and-x64-direct-download-link/
