The change of language in Windows 7 Home and Professional is usually not provided by Microsoft. By using a program like Vistalizator can even validate Windows fail because the program changes essential files from Windows. Read more about it here, among others: [...]
I have therefore the German language files (for now) not reinstalled and get along well with the English version. Especially since I only use as a second system on my Mac Windows.
Sorry, could be not even the German version of Microsoft under [...] Download because the page recognized the key as an OEM version. After all, Windows allowed but install and activate Windows with the Key.
The product entsprich not descriptive in any case.